6. Arrival of winter for Aleutians

6-1 Arrival of winter

In November, low pressure systems often developed like typhoons near the Aleutian Islands, and there were many stormy days. The strong winds and water on the runway had restricted the activities of US military aircraft. Even if their aircraft took off, they often returned on the way or bombed from above clouds. The aircraft accidents due to the bad weather also occurred frequently, and the activities of US military aircraft declined until the end of December, except for the attack on the transport ship "Cheribon-Maru" on Attu Island on November 27. Meanwhile, the Japanese transportation using the light cruisers "Abukuma", "Kiso", and the destroyer "Wakaba" (K-Convoy) was carried out, and 525 independent infantry 302 battalions arrived at Kiska Island on December 3 [4, p380].

During the stormy weather, the US troops strengthened their bases preparing for the next spring offensive operation. The Navy Construction Engineers and Army Engineers built barracks, hangars, warehouses, radio communications stations, piers, and dry docks on Adak Island. A refueling pier, an oil tanks, and ammunition storage were also constructed on a nearby island. The US military not only reinforced their strength, but also carefully improved the facilities to support them.

In order to strengthen transportation to the Kuril Islands and Aleutian Islands, the Japanese military organized the 30th Harbor HQ in Paramushir in late December, and the HQ owned ship engineers, landing companies, maritime transport companies, and ship arsenals. On December 25, six Navy Type Two sea fighters were replenished on Kiska Island, and two army transport vessels, the "Kouan-Maru" and "Yamayuri-Maru", arrived at Attu Island on December 29 [4, p9]. At the time of landing of supplies, the measures were taken to avoid air raids and shorten the staying time in the bay, such as bags and drums filled with supplies are thrown into the sea and pulled up from the shore.

The activities of US military aircraft resumed around the New Year of 1943. The transport ship "Urajio-Maru" that had arrived at Kiska Island was bombed in the bay on December 31. On January 6, the following year, the transport ships "Montoriru-Maru" for Kiska Island and "Kotohira-Maru" for Attu Island were attacked before arriving at their destinations by US military aircraft. "Kotohira-Maru" was loaded with food, assembly barracks, and fuel [3, p196]. "Montoriru-Maru" carried 831 soldiers, some of the 302 independent infantry battalions [4, p391-392]. Due to the distress of these two ships, all supplies and soldiers were lost in the sea. The defense reinforcment plan for February had to be significantly delayed.

In the winter, the most of seaplanes of the Navy 452 air unit were unusable due to not only air raids but also storms and high waves caused by low pressure systems [7, p215]. The storm on January 4 was particularly fierce, and a high wave of 4 m on Kiska Island damaged all seaplanes moored in the bay. Therefore, after that, a hill near the coast was cut open and a dock for the salvage of seaplanes was built. At night and during storms, all of the seaplanes were to be lifted to land. Lifting light single-seater sea fighters were still easier, but heavy three-seater reconnaissance seaplanes were a hard work to pull into the bay and lift to land every day [7, p222]. On Attu Island, some of the food stockpiled was leaked due to the high waves caused by the storm that day. The scarce food could not be adequately replenished until the troops were wiped out in the end of May [3, p196].

6-2 Airfield construction

The airfield on Kiska Island was being built on a flat land north of Kiska Bay. The plan was to build a runway 800 m long and 120 m wide by the end of February, and another 1200 m long runway that intersects it by four months later. The construction began on December 1, 1942, but the progress was significantly delayed due to delays in the material transportation. The construction materials and the tools, such as pickaxes, rope baskets for carrying earth and shovels, arrived on February 4 [3, p201]. The priority was given to the construction of airfield, so the construction of defense facilities, barracks, and the road excavations between defensive positions was postponed. Also, at some opportunities, it seems that bulldozers were sent to Kiska Island [3, p398] and Attu Island [7, p423]. However, according to local records, the childish performance of Japanese bulldozers was not very effective against the hard rocks of the islands [3, p256]. This was not just a problem with construction machinery, but in Japan at that time there were no experienced operators. As a result, truck drivers who saw bulldozers for the first time were devoted to their operation [17, p199]. At that time, Japanese construction machines frequently failed due to poor manufacturing technology, poor materials, and immaturity of operating skills.

When the Allied forces discovered that the Japanese troop was constructing a runway on Kiska Island, they began bombing the construction site on January 20, Therefore, the Japanese had to build the air raid shelters and the fox holes for evacuation near the construction site [3, p202]. Not only the engineering corps but also soldiers were mobilized for the construction work. The average number of workers is almost 600 per day [3, p201]. However, when the weather was good, the work was interrupted by air raids, and when the weather was bad, the construction work did not proceed under the snowstorm [7, p148]. The disruption of supplies, especially the shortage of explosives for blowing up the bedrock, had a serious impact on the construction. In March, most soldiers returned to their original missions to strengthen their defenses, and airfield construction returned to work solely by the engineering corps.

The runway on Kiska Island was roughly completed at the end of April (there is another story that it was completed at the end of March. However, the Japanese War History Series, Senshi-sosho Vol. 21. "Army Operations in the Northeastern <1> has set the progress at the end of March to 55% [3, p278]). Kiska Island, which was frequently hit by air raids, needed bunkers to protect planes, so the fighter squadrons is scheduled to advance in mid-May after the bunker construction would be completed. At the end of May, not only the runway but also the taxiway and bunkers were completed, and the airfield on Kiska Island became available. However, the airfield was never used due to the collapse of Attu Island. Further expansion of the airfield was continued, but the work was discontinued on June 8 due to the start of evacuation operation "Ke-gou", which is described later [3, p279].

Initially, no suitable flat land for airfield was found on Attu Island, but it was found that there was a suitable site in Higashiura (West Arm) at the back of Holtz Bay by the survey after the re-occupation. A construction work on a runway with a width of 60 m and a length of 1000 m began on February 25, when personnel and materials were available. The soil of the airfield construction site was sandy, and it seems that the work was easier than that on Kiska Island [3, p297]. The constructing runway was compacted with human feet, and small rollers were pulled over it to further compact the surface. It was estimated to be completed at the end of May, but was not completed due to the landing of the Allied Forces in early May [3, p298] as described Chapter 8.

6-3 Invasion to Amchitka Island by Allied Forces

The Allied Forces significantly expanded the military facilities on Adak Island in preparation for the invasion, and as part of this, deployed torpedo boats on Adak Island. However, in winter, not only the top-heavy condition on hull by attaching ice made their operations impossible, but the high waves in winter also launched five boats to the shore [4, p399]. After all, the torpedo boats could not be used for any operations, but used only for patrols and transportation of supplies when the sea was calm [10, p47]. Amchitka Island, about 300 km west of Adak Island and only 130 km east of Kiska Island (about half-length between Kiska Island and Attu Island), was a flat island with a good port. If an air base was established by Allied Forces on Amchitka Island, they would be possible to make air raids increasingly during short gaps of fogs or clouds. If so, the Japanese troops on Kiska Island and Attu Island would be like chickens glared at by foxes. The occupation of the island became the next goal for the Allied Forces.

Kinkaid reading in his quarters on Adak, Aleutian Islands, 14 May 1943. https://ww2db.com/image.php?image_id=783

The Allied Forces landing day on Amchitka Island was scheduled for January 5, 1943, but was postponed to January 12 due to the bad weather. Although the day was far from ideal weather, the operation was carried out and 2100 troops landed on Amchitka Island. At that time, the destroyer "Warden" was swept away by strong winds and currents and struck a sunken rock, resulting in 14 people freezing to death in the cold sea [10, p59]. The bad weather continued, and one transport ship ran aground on the following day.

Loss of USS Worden (DD-352)

https://www.history.navy.mil/our-collections/photography/numerical-list-of-images/nara-series/80-g/80-G-70000/80-G-75591.html

Immediately after the landing, the construction of an airfield on Amchitka Island began. The runway site had to be drained from the wetlands and covered with dry earth and sand, but the construction was time consuming because it was too muddy to use for vehicles [10, p60]. The Japanese seafighters which scouted Amchitka Island on January 24, 1943, discovered that Allied Forces had landed on the island and were constructing an air base [4, p384]. The occupation of Amchitka Island by Allied Forces gave a significant impact for Japanese on the defense of the western Aleutian Islands. Once the airbase on the Amchitka Island was completed, it was expected that heavy air raids would make transportation and supply to Kiska Island and Attu Island extremely difficult. The cost of leaving Amchitka Island unattended, knowing that it had a flat land suited for airfield, was expensive. After this, the Japanese military would make several plans to recapture Amchitka Island. However, landing operations on the island already occupied by the Allies could not have been possible given the possible damage. Again, the preparation for Allied invasion by the Japanese was too late.

Several Japanese seafighters and reconnaissance seaplanes bombed Amchitka Island five times from February 1 to 16 to disturb the airfield construction [7, p207]. However, the runway on Amchitka Island was completed on February 18, and P-40 and P-38 fighters advanced [8, p24]. The two Japanese seafighters that were scouted for the Amchitka Island on February 19 had not returned. Kiska Island radar had found that the two airplanes fought aerial battles with about 20 US fighters that took off from Amchitka Island to intercept them [7, p214]. One of the Japanese pilots was Air Sergeant Sasaki Hajime, known as the Ace, who shot down more than 20 enemy airplanes. They are believed to have reached a spectacular end during the engagement.

6-4 The fourth reinforcement

Major Iwakoshi Shinroku of the Imperial General Headquarters visited Kiska Island and Attu Island (without landing) on January 9 and 10. He found that only 40% of weapons, 60% of food, and 20% of building materials arrived due to the stormy weather and the obstructions by enemy submarines and aircraft. He reported on January 28 that, without an increase of one infantry battalion each by March, both islands would have the same fate as Guadalcanal Island [3, p537]. On February 1, Admiral Ichinomiya Nobuyuki, Chief of Staff of the Fifth Fleet, said at the Navy General Staff office that the enemy would invade after isolating Attu Island and Kiska Island by blocking the transportation, so the future policy should prioritize the transportation of the necessary supplies by the end of February. However, they estimated that the US naval forces for the invasion were about 10 ships including seaplane tenders [18, p138]. At that time, the Fifth Fleet command had insisted on the necessity to invade Amchitka Island [4, p416-417], but the result was that the Allied Forces had landed on Attu Island in May before the concrete plan for invading Amchitka Island was decided.

The Allied occupation of Amchitka Island had made the situation in the western Aleutian area imminent. The Imperial General Headquarters issued Continental Order No. 747 on February 5, and began strengthening the defenses of Attu Island and Kiska Island for the fourth time. The North Army Force, which had been tasked with defending Hokkaido and South Sakhalin and transporting supplements to Kiska Island and Attu Island, was suddenly changed to a new operational army (actual warfare army) called the "Northern Army Force" to take the charge for defending the Aleutian area [18, p140, 144]. Lieutenant General Kiichiro Higuchi, former commander of the Northern Army Force, was appointed as the new commander of the Northern Army Force.

Due to the central agreement at the Imperial General Headquarters on the same day, the North Sea Garrison left under the command of the Fifth Fleet and came under the command of newly formed Northern Army Force of the Imperial Army. The first district battalion (3 infantry battalions, 1 artillery battalion, 1 anti-aircraft battalion, 1 engineer battalion, 1 communication company) of the North Sea Garrison, headed by Colonel Masaji Sato, would defend Kisuka Island; The second district battalion (1 infantry battalion, 1 artillery battalion, 1 anti-aircraft battalion, 1 engineer company, 1 communication company), headed by Colonel Yasuyo Yamazaki, would be responsible for the defense of Attu Island [3, p245]. These became the turning point of their fates. In addition, the Navy decided to dispatch aircraft when the airfield would be completed, which was to be specified separately in the Central Agreement in the last November. However, because the airfield was built by the Army, the Navy was prudent about advancing aircraft until the airfield would be completed including the taxiways and the bunkers [19, p191]. The agreement was also to strengthen the defense of the entire Kuril Islands, and garrisons would be placed in the northern, central, and southern Kuril Islands. This defense plan also led to the construction of 15 new airfields in those areas, in addition to Sakhalin and Hokkaido, from late 1943 to early 1944 [3, p312].

Under this military central agreement, the Imperial General Headquarters decided to build defense base groups and air bases centered on Attu Island and Kiska Island by the end of March. The materials and troops for them would be transported by the end of February under the name of Operation "A-Gou" [4, p421]. And for escort of transport, four ships including the heavy cruiser "Maya" and the submarine "I-31" were incorporated into the Fifth Fleet. As a result, "Maya" would later participate in the Battle of the Komandorski Islands. This military central agreement presupposed the completion of the airfield as the condition for dispatching aircraft to Kiska Island. However, it was clear that if the US air base on Amchitka Island was completed, it would be deprived of air superiority over Kiska Island at all times. The commander of the North Sea Garrison was concerned that the air superiority would need to be secured first for the airfield construction [4, p242].

At the time of February 18, the six convoy transports planned for Operation "A-Gou" in mid-February were as follows [4, p436-438].

• The 14th Convoy for Kiska deported on February 13 (transport vessel "Sakito-Maru", "Shuko-Maru", light cruiser "Kiso", destroyer "Wakaba", "Hatsushimo")  
• The 16th Convoy for Attu deported on February 14 (transport vessel "Akagane-Maru", coast defense ship "Hachijo")
• The 15th Convoy for Kiska deported on February 18 (transport vessel "Awata-Maru", light cruiser "Abukuma", destroyer "Ikadzuchi" )  
• The first 18th Convoy for Attu would deport on February 19 (transport vessel "D?b?-Maru")
• The 17th Convoy for Kiska would deport on February 24 (transport vessel "Fujikage-Maru", light cruiser "Abukuma", "Kiso" )
•  The second 18th Convoy for Attu would deport on February 24 (transport vessel "Yamayuri-Maru")

During this operation, on February 19, the US fleet made the naval gunfire on Attu Island as described below. As a result, the 16th Convoy "Akagane-Maru" was captured and sunk by the US fleet on the way to Attu Island on the February 20. The 14th Convoy turned back on the way and the remaining planned convoys (17th Convoy and the first and the second 18th Convoy) were canceled [4, p440]. Only the 15th Convoy, which loaded approximately 400 air defense troops, 8 25 mm machine guns, 8 13 mm machine guns, 20,000 bullets, 3 searchlights, 11 trucks, other landing crafts and protective materials, successfully transported to Kiska Island on February 22 [4, p440]. Totally, the successful transport operations were only the 15th Convoy above mentioned and the 13th Convoy (transport ship "Yamayurimaru") that had arrived at Attu Island on February 12. The remaining transports by 5 Convoys were ended unsuccessful.

6-5 The naval gunfire on Attu Island and sinking of Akagane-Maru

The Allied forces that occupied Amchitka Island feared counterattacks by the Japanese. It was believed that reinforcements would still be continued on Attu Island, which was far from Amchitka Island. Therefore, on February 19, the heavy cruiser "Indianapolis" led by General McMorris, the light cruiser "Richmond", the destroyers "Coghlan", "Gillespie", "Bankloft", and "Coldwell" [8, p24] fired the land facilities at Chichagof Harbor on Attu Island for 2 hours and 20 minutes [4, p439]. Despite the fact that the Japanese reconnaissance seaplanes in the 452 air unit had found the US fleet off Attu Island on February 16, 17, and 19 [4, p436], the naval gunfire on Attu Island was a surprise attack for the Japanese. After the bombardment, the US fleet pretended to retreat to the east and cleverly turned its course to the southwest of Attu Island [8, p25]. This was to prevent Japanese transport vessels from entering Attu Island after the US fleet would have left.

After being received the naval gunfire by the US fleet, the three Japanese reconnaissance seaplanes tried to chase the US fleet, but they could not find them due to bad weather. The commander of the Northern Army Force instructed the transport ship "Akagane-Maru", which had been waiting off the coast of Attu Island, to enter Attu Island [4, p439]. The US fleet discovered a Japanese transport ship south of Attu Island by radar around 1830 on the February 20. This was the "Akagane-Maru" that was about to enter Attu Island. This was just after the coast defense ship "Hachijo", which had been escorting her, had returned because they approached Attu Island. The US fleet fired the "Akagane-Maru" with artillery, but the ship did not sink, so the fleet launched six torpedoes. However, all the torpedoes came off or exploded before the ship. Inevitably, the US fleet fired again and finally sink it [8, p26]. The naval gunfire on Attu Island gave a small impact on the land force, but as mentioned above, it was effective in blocking the five transportations by the Japanese convoy. For the Japanese, this blocking was a major obstacle for the garrisons to strengthen their defenses to be completed by the end of March.

(to be continued)

References are listed in "Reference" in the upper right-hand side.

5. The reinforcement of defense on the western Aleutians and invasion on Adak Island by Allied forces

 5-1 The first change in defense policy

5.1.1 Shift of defense policy in the Japanese military

On June 7, the Operations Division of the Navy General Staff called on the Operations Division of the Army General Staff to explain the war situation and to exchange opinions on future operations. At that time, they agreed on the considering the permanent occupation of the western Aleutian Islands [4, p276]. The reason for this was to prevent from establishing Allied bases for air raids on the mainland of Japan. In addition, it was introduced the view by Commander-in-Chief of the Fifth Fleet that "We found to be able to overwinter on both Attu and Kiska Islands. If we are once removed, reoccupying them will be difficult. So we should continue to occupy both islands." [3, p125]. The significance of blocking of linkage between the US and Soviet Union was also taken into consideration.

As a result, on June 23, the Imperial General Headquarters issued the order of the permanent occupation of Attu Island and Kiska Island with Great Army Ordinance No. 647 [4, p277]. As mentioned above, on June 25, the North Sea Detachment came under the direct control of the Imperial General Headquarters [3, p124]. Regarding this policy change, the Japanese War History Series, Senshi Sosho Vol.9 "Pacific War Navy Operation History" also states that "with the opinion of the Commander-in-Chief of the Fifth Fleet and the views of both politics and strategy after the Battle of Midway ..." [ 4, p277]. But that would have required a drastic review of the occupation strategy such as creating air bases. It was quite possible that the US military would build air bases further west of the eastern Aleutian and try to recapture their own territory while threatening the supply line to Kiska and Attu.

The member of Landing Force on board the destroyer "Wakaba" conducted the surveys on Shemya Island and Amchitka Island on June 12. Shemya Island, 50 km east of Attu Island, was found to have dry grasslands suitable for airfields. It was also found that Amchitka Island, 130 km southwest of Kiska Island, had a flat land that could be used as a crash-landing airfield with a little construction [4, p256]. However, the Imperial General Headquarters left both islands unattended (The landing operation of Shemya Island was carried out in November 1942 but was canceled before landing as described later). The fact that Amchitka Island was left unattended and an airfield was built there by the US military in February of the following year became fatal to the defense of the western Aleutian Islands for Japan, as described later.

Map of the western Aleutians.

The Fifth Fleet Command requested the Navy General Staff and the Combined Fleet Command to urgently construct airfields for defense, but both high commands were reluctant to dispatch land airplanes to the western Aleutian Islands. Lieutenant Colonel Tatsukichi Mishiro, who was in charge of aviation at the Imperial Navy General Staff, said, "The purpose of the occupation is to prevent the enemy from using these islands" [4, p298]. This shows the Navy General Staff's belief that the Allied Forces would not attack on these islands if they were occupied by the Japanese troops. 

The Navy General Staff underestimated the US counterattack in the western Aleutian Islands and thought that they did not want to involve valuable air power in the attrition warfare. For this reason, the Navy General Staff determined to defend the islands with only ground troops and seaplanes [4, p298]. The permanent occupations of these islands without airbases became the first change in defense policy after landing, which had made the establishment of defense slower than the attack of Allied Forces.

Since the Fifth Fleet command requested the formation of a base corps to the Navy General Staff, the Navy Fifth Guard Corps was established in Kiska Island on July 1, 1942, based on the Navy Third landing Force [4, p280]. However, due to the frequent air raids by US bombers, the Northern Unit again requested the construction of airfield. As a result, the Navy General Staff agreed on June 23 to send investigators for airfield construction of next year. The Combined Fleet Command also changed its mind on July 21 to research the weather conditions this year for considering airfield construction of next year [4, p299]. In any case, there were no plans to build airfields immediately. 

Following may be the hindsight-based opinion; If the Japanese military had started transporting materials for airfield and constructing an airfield at this time before the air raids intensified, the Japanese military might have been able to complete an airfield in Kiska Island by the time the US constructed the airfield on Adak Island in mid-September.

Due to the first Japanese policy of occupying the islands by Autumn and the underestimation of US forces, the cannons installed were only four 12 cm cannons, four 7 cm anti-aircraft guns on Kiska Island, and two 7.6 cm cannons and two battalion guns on Attu Island [4, p278]. In response to the unexpected counterattacks by the US air force, the strengthening of defense was immediately considered even though it had just after landed.

To reinforce the defense of Kiska Island, the followings were determined to be sent to Kiska Island by the transport fleet in early July [4, p281]: the Navy Second Landing Force, a field artillery unit, a construction corps, six 15 cm artillery, four 12 cm anti-aircraft guns, four 7 cm field anti-aircraft guns, eight mountain guns, eight anti-tank guns, ten other guns, six midget submarines (Type A Kou-hyouteki-class submarine), and six seaplane fighters. 

Along with this transportation, the second interception operation was set up by the Northern Unit. On June 28, the Northern Unit of almost the same force as the previous one, including the aircraft carriers (excluding the carrier "Jun-yo"　by the engine trouble), waited at the sea east of Hokkaido [4, p263]. However, the US fleet did not appear, so the two Northern Fleet interception operations by the Imperial Navy had no effect. On the other hand, the transport fleet was targeted by the US submarines near Kiska Island as described below.

5.1.2 Deployment of midget submarines

The transport fleet consisted of the seaplane tender "Chiyoda" carrying midget submarines and the Navy Type 2 seaplane fighters for strengthening the defense, the cargo ship "Aruzenchina Maru", and the destroyers "Arare", "Kasumi", "Shiranui". They arrived at Kiska Island in the fog on July 4. "Chiyoda" and "Aruzenchina Maru" managed to berth in Kiska Bay in the fog, but three destroyers berthed outside the bay. These destroyers were attacked by the US submarine "Growler", which sank "Arare" and wrecked the other two [4, p272]. 

On July 5, the destroyer "Nenohi" was sunk off the coast of Agattu Island by the US submarine "Triton." As mentioned earlier, on July 1, two submarine chasers were sunk by the US submarine "Grunion" outside Kiska Bay. The soldiers on Kiska Island realized the harshness of the future by the facts that the destroyers and submarines chasers that were supposed to bury submarines were sunk by submarines. However, the Navy Type 2 seaplane fighters and the midget submarines carried by "Chiyoda" were successfully landed. This landing reinforced the various cannons and 350 men of engineering corps for the construction of midget submarine bases.

The construction of the midget submarine base began in July in the midst of the air raid. It took about 3 months to complete a 100-meter slide, a hangar that dug down the coast, and boilers. However, after several training in the bay, all the midget submarines became unusable one after another due to flooding of the submarines due to stormy weather, poor insulation, and the damage to boilers and generators by the bombing [7, p91]. Under the severe weather and the air superiority of US air forces, the midget submarines were never used in any operation.

Three Japanese Type A-class midget submarines wrecked by demolition charges, at a former Japanese base on Kiska Island. (September 7, 1943)
https://ww2db.com/image.php?image_id=3332

The cargo ship "Kano Maru" heading for Kiska Island via Attu Island on July 31 was hit by a torpedo from a US submarine outside Kiska Bay [4, p314]. The next torpedo fired unexploded, so the submarine surfaced because she seemed to try to sink the "Kano Maru" in a gun battle. "Kano Maru" fired an 8 cm cannon in front of her, and the shell hit the submarine's command tower and sank the submarine [4, p327]. This sunken submarine has been recently identified as the US submarine "Grunion". However, in the United States, it is speculated that her sinking is by a damage to the elevator due to the torpedo launched by herself [14]."Kano Maru" was towed into Kiska Bay and was trying to repair it, but she was laid down on September 15 by the air raid.

Attu Island was out of the attack range of US bombers, so no anti-aircraft unit was deployed. However, seeing the situation on Kiska Island, the Imperial Army decided to deploy an anti-aircraft company on Attu Island. Four 7 cm anti-aircraft guns, five 20 mm anti-aircraft guns and about 40 freight vehicles were landed on Attu Island on August 17. However, there were no roads on Attu Island, so the vehicles were hardly available [7, p103]. Moreover, due to the change in defense policy immediately after this as described later, most of the vehicles were abandoned at the removal from Attu Island in September, except for a few vehicles such as tow tractors and ammunition vehicles [7, p104].

5.1.3 Install of radar on Kiska Island

The Navy 1-Gou radar (the first type) was sent to Kiska Island, and the large antenna was installed on the summit of the mountain called Katsura-Yama in August. The radar was supposed to have the detection range of 100 km, but was actually able to capture aircraft 300 km away [7, p239]. The operation unit of the radar was not composed of military personnel but of civilian employees and engineers who had graduated from industrial schools or radio communication schools. Using their expertise and experience, they could detect enemy aircraft from the reflected waveform on the cathode ray tube and reported it to the air defense unit.

Their report was very useful for ground soldiers to evacuate before the air raid. The anti-aircraft units also listened to the course of the enemy airplanes, waited for them with preparing, and shot down them where the enemy aircraft emerged over the mountain [7, p248]. Furthermore, the seaplane fighters took off first after being contacted by the air defense unit, and then headed for interception in the air according to the radio instructions of the enemy's position [7, p212]. 

Some members of radar unit stated that the radar was believed by soldiers who didn't know it as a super-large telescope that could see everything. Not only were they able to reliably capture the enemy airplanes, but around February 1943, from the waveform reflected on the cathode ray tube, they could know whether the target was bombers or fighters by aircraft type [7, p241].

The radar antenna on Kiska Island was guessed to have caught the US military's attention, but the antenna of the radar was not attacked even by the numerous air raids. The production amount of the Navy 1-Gou radar was about 30, and some of them were also sent to the battle fields in South Pacific, but the one on Kiska Island performed best [15, p94]. It is worth noting that in the early stage of the war, the Japanese troops succeeded in constructing the effective interception system using radar. It is regrettable for Japan that the system was used for the seaplane fighters and the number of them was quite small.

5.1.4 Activities of anti-aircraft units and seaplane fighters for defense

The six Navy Type 2 seaplanes transported to Kiska Island by the seaplane tender "Chiyoda" immediately fought the air battle with the B-24 bomber on July 8. They contributed to the defense to some extent together with the anti-aircraft units. The 7 cm field anti-aircraft gun (Army Type 88 75 mm AA gun) deployed by the Imperial Navy on Kiska Island was inherited from the Imperial Army. However, taking advantage of the fact that the Army and Navy had the same type of anti-aircraft guns on Kiska Island, the information and ammunition possessed by both were unified. The training was also carried out in cooperation with them, so the guns were operated efficiently [7, p226]. It was unusual elsewhere in the Japanese military.

Captain Seiichi Kakizaki, Chief of the Fifth Guard (Deputy Officer of the Navy Third Special Landing Force), stated that the Army's 7 cm field anti-aircraft gun was the suitable gun that was very easy to use and more agile than the Navy's 12 cm anti-aircraft gun [7, p229]. The Imperial Navy did not have this size of anti-aircraft guns including ships. This type of gun also defended the ship from the air raid. Captain Asazo Wada, the commander of the Imperial Army 22nd anti-aircraft gun company, installed three 7 cm field anti-aircraft guns on the transport ship "Boruneo Maru" when his company was deployed to Kiska Island. He then coordinated in advance with the captain of the ship how to navigate when enemy planes came to attack. As a result, they succeeded in destroying the US bombers at sea, and the "Boruneo Maru" could arrive safely on Kiska Island [7, p111].

The Navy Type 2 seaplane fighter (Rufe) was a floatplane developed based on Navy Type Zero fighter and was equipped with 20 mm machine guns. However, US bombers such as the B-17 and B-24 were faster than this, so Navy Type 2 seaplane fighters could not hit more than three times. Therefore, even if it could damage them, it was difficult to shoot them down [7, p212]. 

After the opening of the US Army Air Base on Adak Island in September, the Navy Type 2 seaplane fighters fought with US Army fighters such as P-39, P-40, and P-38. The speed of Navy Type 2 seaplane fighter was slower than that of Navy Type Zero fighter due to the large float attached, but the turning performance increased due to its buoyancy. Pilots of the Navy Type 2 seaplane fighter on Kiska Island included veterans with excellent skills, and it was said that the US fighters challenged the Navy Type 2 seaplane fighters only when they were superior [7, p213]. 

As the results of the air battle until August 15, one B-17 bomber and one seaplane reconnaissance aircraft were shot down. One B-17 and one B-24 bomber were damaged. There was no damage to the Japanese pilots [4, p297]. By September 15, the results of battle were five shot down and two destroyed, and the Japanese seaplane fighter had two unreturned and two damaged [4, p308].

The Navy Type 2 seaplane fighter (Rufe)

https://ja.wikipedia.org/wiki/%E4%BA%8C%E5%BC%8F%E6%B0%B4%E4%B8%8A%E6%88%A6%E9%97%98%E6%A9%9F#/media/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:A6M2-N_Rufe.jpg

At that time, the production of Navy Type 2 seaplane fighter was from 10 to 20 per month, and the deployments of them were on Kiska Island and islands in the south Pacific. In the Navy Type 2 seaplane fighter unit on Kiska Island, the aircraft was exhausted in battles and stormy weather, and repeatedly replenished. The replenishment of it was carried out at most once a month on a seaplane tender. As there were some periods when there were no fighters in operation, so the interception on Kiska Island was limited. The seaplane unit on Kiska Island was formed as the Fifth Air Corps on August 5, and became the 452 Navy Air Corps in November.

5.1.5 Bombardment on Kiska Island by US fleet

As the US military considered that the bombing by large bombers was not be effective by clouds, they boldly planned to carry out the bombardment by warships for Kiska Island. The fleet consisted of five cruisers, five destroyers, and four minesweepers had left Kodiak for the attack scheduled on July 23, but it turned back near Kiska Island due to a fog. The fleet had set sail again on July 27, but again encountered a thick fog and turned back. Along the way the destroyer "Monaghan" and the minesweeper "Long" collided in the fog, and the minesweepers "Lumberton" and "Chandler" also collided [10, p41]. These four ships returned to Kodiak and took several months to repair.

Major General Theobald of the North Pacific Force transferred control of the North Pacific fleet to Brigadier General William Smith on August 3, according to the direction by Admiral Nimitz [2, p46]. On August 8, the US fleet led by Brigadier General Smith, which was consisted of the heavy cruisers "Indianapolis", "Louisville", light cruisers "Honolulu", "St. Louis", "Nashville", and four destroyers, approached Kiska Island. The day was cloudy and foggy. The fleet once rushed into the coast using radar, but lost their position due to the fog, so it returned offshore [10, p41]. The fleet launched the reconnaissance seaplanes to survey the fog near Kiska Island. They confirmed the fog cleared, then approached the island again and fired [8, p19].

Cruiser USS Louisville steamed out of Kuluk Bay, Adak, Aleutian Islands, bound for operations against Attu, 25 Apr 1943

https://ww2db.com/image.php?image_id=3665

There were ten cargo ships, four submarines, and one light cruiser in Kiska Bay. The US fleet took the position of southwest of the peninsula called South Head, southwest of Kiska Bay, because the Japanese destroyers were wary of the entrance to the bay. The fleet was unable to aim directly into Kiska Bay behind the peninsula, so it fired by indirect pointing [8, p19].

Fifth Ground Corps in Kiska had just been warned by Northern Unit as the US troops landed on Guadalcanal Island in the South Pacific on August 7, the day before. However, the attack on this day by the US fleet on Kiska Island was due to fog, not in line with the landing operation on Guadalcanal Island. This attack was a surprise attack for the Japanese troops. The Japanese troops noticed the enemy fleet's approaching after discovering the US reconnaissance seaplanes in the sky, and immediately after that, they received heavy naval gunfire [7, p128]. Since the US reconnaissance seaplanes were intercepted by the Japanese seaplane fighters over Kiska Island, one was shot down and three or more were damaged. The Navy Type 2 seaplane fighters also shot the US destroyer "Case". In addition, The Navy Type 97 large flying boats bombed the US fleet from above the clouds, but the US fleet was not damaged [2, p46].

The US fleet fired 7,000 5-8 inch shells. From the second half, the air raids by bombers were also carried out to support the evacuation of the fleet. However, the damage to Kiska Island was only one seaplane fighter damaged and two soldiers killed in action [4, p290]. As a result of later air reconnaissance, the US military determined that although it sank one destroyer and one cargo ship and damaged one cargo ship, it had little effect on ground troops. However, it was not clear whether those damages were due to this naval gunfire or the previous bombings [10, p44]. Brigadier General Smith thought that air strikes were more effective than naval gunfire. Buckner, on the other hand, was wondering the Theobald's undaring instructions for bombing from high altitudes [2, p47].

5-2 The second change in defense policy

5.2.1 Relocation of Attu's garrison to Kiska Island

For the Japanese, the US counterattack on Kiska Island was faster and more powerful than expected. The bombing and naval gunfire on Kiska Island seemed for the Japanese that the Allied Forces would focus on the recapture of Kiska Island. The landing on Guadalcanal Island by Allied Forces also caused concerns about the defense of Kiska Island [3, p146]. The Fifth Fleet command raised the opinion to the Imperial General Headquarters that it would be difficult to secure the western Aleutian Islands for a long time in this situation. The Imperial General Headquarters decided to move Attu Island's garrison to Kiska Island in order to unite and strengthen the defense. It was the second change in defense policy.

On August 25, the Imperial General Headquarters ordered the North Sea Detachment on Attu Island (Attu's garrison) that they relocate to Kiska Island and enter under the command of the Commander-in-Chief of the Fifth Fleet. The advance team of the North Sea Detachment departed for Kiska Island on the transport ship "Nagata Maru" on August 26. However, the transfer of the main troops by the transport ship "Imizu Maru" took time due to stormy weather. In addition, another transport ship "Nojima Maru" assigned to the transfer had been wrecked by the air raid on Kiska Island, so the transfer was delayed. The relocation of Attu's main troops was completed by two separate transports on September 11 and 18. When the North Sea Detachment relocated, they took the part of barracks panel to Kiska Island. However, they burned the rest of the wooden materials, food, and anything else that could be utilized by the enemy on Attu Island [3, p147].

Following the change in defense policy, on September 15, the Imperial Navy formed the Navy 51st Base Force on Kiska Island and appointed Maj. Gen. Katsumi Akiyama as the commander [4, p339]. The Imperial Army occupied Attu Island in November again, but the abandonment of Attu Island and the incineration of most of materials delayed the construction of defense facilities after the reoccupation, which became one of the reasons that the Attu's garrison was wiped out in a short period of time in May 1943.

5.2.2 Occupation of Adak Island by the Allied Forces

The Unite States concerned that Japanese troops would build an airfield on Amchitka Island and occupy Adak Island (400 km east of Kiska Island). Residents of Alaska were also worried about the Japanese invasion to the east. To prevent this, General Dewitt, Commander-in-Chief of the Western Army, felt the need to advance bases west. Buckner of the army Alaskan Defense Force proposed to build an air base on Tanaga Island (300 km east of Kiska Island) and once obtained the approval of the Joint Chiefs of Staff of the United States. 

However, Theobald of the North Pacific Force opposed this, saying it was too close to Kiska Island, and directly appealed to Ernest King, Commander-in-Chief of the United States Fleet, to build a base on Adak Island [5, p14]. Eventually, George Marshall, Chief of Staff of the United States Army, instructed Dewitt (and Buckner ) to occupy Adak Island [16, p14]. Due to the controversy involving the Joint Chiefs of Staff of the United States, the operation to occupy Adak Island was delayed by about a month.

The Allied Forces landed the reconnaissance unit on Adak Island on August 28, confirming the absence of Japanese troops, and then landed 4,500 Army soldiers on August 30. On the same day, the engineer corps also landed. They leveled the ground with bulldozers, dug a ditch, and drained water. Mesh iron plates (38 cm x 3 m) of sixty thousand, called Marston mats, were laid there in haste to construct a runway. Due to the extraordinary efforts, the 1500 m long and 150 m wide runway was completed on September 12 [10, p53]. However, due to the runway built on poorly drained land, when it rained, high sprays were generated every time the aircraft took off and landed.

Marston mat laid later on the Navy's auxiliary field on Tanaga Island in the Aleutians.

https://en.wikipedia.org/wiki/Marston_Mat#/media/File:Marston_mat_laid_by_CB_45.jpg

On August 28, a Japanese reconnaissance seaplane found a light cruiser and a destroyer in Nazan Bay, Atka Island. On the next day, three Japanese seaplanes attacked on Atka Island, but there were no ships there. They bombed the berthed flying boats, but they were not damaged. 

Three Japanese submarines, "Ro-61", "Ro-62", and "Ro-64", were also ordered to attack on Nazan Bay. The submarine "Ro-61" entered Nazan Bay and hit a cruiser with a torpedo [4, p302]. However, "Ro-61" was forced to surface by the depth charge attacks by the Catalina flying boats and the destroyer "Raid", and was sunk by the bombardment of the destroyer. Five of her crew were rescued by the destroyer and taken prisoner of war [2, p49]. The cruiser "Ro-61" attacked was the seaplane tender "Casco", and she was disabled in the bay by the hit of torpedo, but she was towed back to Dutch Harbor [8, p21]. In addition, the submarine "Ro-62" reported the discovery of the US fleet, so the commander of the Northern Unit prepared for the attack by the US fleet, but the movement of the US fleet was not to attack the Japanese troops but to land on Adak Island.

Seaplane tender "Casco" in Massacre Bay at Attu Island in the Aleutians in about May 1943. A PBY-5A Catalina patrol bomber is taking off on a patrol.

https://www.history.navy.mil/our-collections/photography/numerical-list-of-images/nara-series/80-g/80-G-60000/80-G-65978.html

On September 4, the fighter planes raided Kiska Island for the first time. They were P-38 fighters from Fort Glen Air Base [3, p154]. The Japanese troops suspected that the US military might advance their air base to the west because short-range land fighters had attacked on Kiska Island. The Japanese might not have known P-38 had a long range. However, because there was no air raid after that, the Japanese troops did not notice that Adak Island had been occupied. The US military deployed 15 B-24 bombers, 15 P-38 fighters, and 16 P-39 fighters on Adak Island on September 13 [10, p53]. The base on Adak Island was subsequently expanded to the large base with 9,000 soldiers and personnel.

 P-38 fighters in the airbase in Adak Island

https://en.wikipedia.org/wiki/Naval_Air_Facility_Adak#/media/File:54th_Fighter_Squadron_P-38s_Adak_Alaska.jpg

5.2.3 Air raid with fighter escort

The US air forces made the large-scale air raid on Kiska Island from Adak Island on September 15. The air-raid alarm was issued in advance because the radar on Kiska Island had caught the enemy airplanes. However, this was not the bombing by a small number of bombers until then, but the first large-scale bombing with 12 B-24 bombers and 28 P-38 and P-39 fighters joining the escort. Moreover, the tactics were changed to make the bombing effective; the bombers bombed from low altitudes instead of high altitudes [2, p50]. 

The bombing and shooting damaged the cargo vessel "Nojima Maru" [4, p307], damaged two submarines "Ro-63" and "Ro-68", and also destroyed land facilities [4, p341]. Four Navy Type 2 seaplane fighters intercepted shot down of five enemy airplanes [4, p313]. Meanwhile, two Japanese seaplane fighters were shot down and one was wrecked. According to the US materials, their damage was the loss of two P-38 fighters that collided in the air [2, p50]. The air battle left only one seaplane fighter on Kiska Island for the Japanese air force.

The US air force tried to expand the outcome, but the aircraft could not fly for the next 10 days due to the bad weather. Meanwhile, the relocation of the Attu's garrison to Kiska Island was successfully completed. However, when the weather improved, large-scale air raids took place on September 26, 29, and 30. On September 26, the submarine "Ro-67" was damaged by the bombing in Kiska Bay [4, p341]. On October 1, a Japanese reconnaissance seaplane finally found the US air base on Adak Island [4, p331]. The Japanese seaplanes air-raided the air base on Adak Island on the night of October 2 and 3 [4, p332]. The submarine "Ro-62" and the submarine "Ro-65" also attacked on Kuluk Bay in Adak Island, but neither was able to get results [4, p341]. 

The Japanese military seems to have been surprised at the sudden appearance of the air base on Adak Island. However, the Japanese military's response to the advance of the air base to Adak Island was only the replenishment of seaplane fighters and the transport of facility materials and ammunition for air defense to Kiska Island [4, p334].

The establishment of the US air base on Adak Island had significantly increased the frequency of air raids on Kiska, and the fighter support to US bombers had made it difficult to intercept by the seaplane fighters. On September 25, the "Kimikawa Maru" replenished Kiska Island with six seaplane fighters and two reconnaissance seaplanes. However, in the battles after the September 26, there left only one seaplane fighter on October 4, and one reconnaissance seaplane on October 10 [4, p340]. The Fifth Fleet command had requested the further replenishment of seaplane fighters, but the production could not keep up with the exhaustion. Nevertheless, the number of seaplane fighter assigned on Kiska Island was increased to 12, and the commander of the Northern Unit decided to transport five seaplane fighters and three reconnaissance seaplanes to Kiska Island on October 13 [4, p336].

On October 7, the cargo ship "Boruneo Maru" was laid down by the bombing in Gertrude Cove on Kiska Island. The submarine chasers were also damaged on October 9 and 10, and the vessels temporarily left Kiska Island [4, p334]. In addition, a large amount of land supplies and ammunition on Kiska Island were burned down in the air raid on the October 15 [4, p334]. 

After this, destroyers began to be used for transportation. However, on October 17, the destroyers "Oboro" and "Hatsuharu" carrying ammunition were attacked by six B-26 bombers north of Kiska Island. As a result, "Oboro" sank and "Hatsuharu" was damaged [4, p334]. For the transport using destroyers, they entered Kiska Bay at night and were forced to unload in a short period of time [4, p338]. 

Moreover, on October 26, the cargo ship "Keizan Maru" loaded with supplies to Kiska Island was sunk by the US submarine S-31 in Suribachi Bay, Paramushir Island [2, p50]. The activities of US submarines had also become active around the northern Kuril Islands.

The Japanese troops on Kiska Island needed solid underground shelters to withstand the large-scale bombings that are expected to continue. Kiska Island troops stopped constructing the defense facilities and began excavating the underground air raid shelters. From the investigation of bomb marks, the underground pit was installed at a depth of 10 m or more [7, p141]. 

The materials for construction such as drifters were urgently transported by the destroyer "Wakaba" on October 16 [4, p337]. The construction tools of the Japanese troops were only rock drills, pickaxes, and shovels. The excavation of hard rock under the tundra was extremely hard work for them. The soldiers had no choice but to endure the US air raids in the underground shelters. However, thanks to the air raid shelters, they were able to avoid suffering serious damages.

In mid-October, the US fleet again planned to bombard Kiska Island. However, at that time, the battles around Guadalcanal Island in the South Pacific were being culminated, and the US Navy had to pull out several cruisers from the Aleutian area. As a result, the naval gunfire for Kiska Island was ceased [8, p22]. In December, some of the remaining ships were also diverted to the South Pacific, leaving the North Pacific fleet with only two light cruisers, four destroyers and a few torpedo boats, excluding submarines [4, p399]. Although another naval gunfire on Kiska Island was not realized, the US Navy's fighting sprit in the North Pacific seems to have been high and aggressive.

5-3 The third change in defense policy

5.3.1 Review of the defense policy

Since October, Kiska Island had been exposed to the air raids by fighters and bombers, and US Navy vessels have frequently appeared nearby. The construction of airfield on Adak Island strengthened the sea and air attacks on Kiska Island. On the other hand, the Japanese military had no means to counter them, and the situation of transportation to Attu Island and Kiska Island became difficult. Moreover, due to the tense war situation in the South Pacific, it was difficult for Japan to reinforce the naval power toward Aleutian. 

On October 8, information was exchanged with the Army and Navy at the Imperial General Headquarters. The situation judgment there was as follows: "The US military is trying to weaken the power of the Japanese forces by cutting off the long supply line. It may not be possible to be invaded soon due to the operations in the South Pacific, but it is likely that the invasion by Allied Forces will take place next spring. Therefore, the Japanese military needs to prepare it by the end of March" [4, p356]. It should be noted that at this point the Imperial General Headquarters had already expected invasions by Allied Forces of the next spring.

The commander of the Navy 51st Base Force on Kiska Island proposed to capture Adak Island. He also requested the reinforcement of land planes and submarines if that was difficult. The Fifth Fleet Command upheld the proposal of the Navy 51st Base Force, but they decided that it would be difficult to capture Adak Island. The Fifth Fleet Command requested to the Navy General Staff the reinforcement according to the proposition by the Navy 51st Base Force. However, the Navy General Staff only replenished seaplane fighters and deployed additional two submarines and two destroyers to the Fifth Fleet [4, p358]. The Fifth Fleet command thought that no matter how much ground troops were strengthened, it was difficult to stop the enemy's invasion without deployment of air forces. Rather, the Fifth Fleet Command was considering retreat from the Aleutian Islands during the winter months [4, p358-359].

Although the Navy General Staff did not agree with the dispatch of land planes, the atmosphere in the Navy General Staff changed to the construction of airfields, partly due to the demands of the Fifth Fleet [4, p362]. On the other hand, the Combined Fleet command continued to consider securing only by ground troops. The Combined Fleet command was inactive to the situation around Aleutian Islands because they were busy responding to the Solomon Islands, which was the main battlefield.

On October 12, the chief of the second section of Army General Staff, who saw the attitude of the Navy, said, "I think it is necessary to secure the Kiska area. The ideas within the Navy are scattered and complicated, and I hope they should resolve this." [4, p360]. Rather, from around this time, the Imperial Army began to place more importance on the western Aleutian Islands as a key point for the battle between Japan and the United States and the prevention of US-Soviet alliances [3, p167].

Although the Imperial Army once abandoned Attu Island, they thought it would be possible for US to build an air base on Attu Island using its high construction ability. The Navy also believed that the construction of an air base on Attu would endanger Kiska Island [3, p168]. The Navy General Staff had the meeting on October 14 regarding the defense of the western Aleutian Islands, and around October 17, they were decided to secure Attu Island again [4, p364].

On October 21, the meeting was held in Ominato between the Fifth Fleet Command, Lieutenant Colonel Sakuo Mikami, Chief of Staff of the Imperial Navy General Staff, and Major Ryuzo Sejima, Chief of Staff of the Imperial Army General Staff. There is no record left on this meeting, but it is speculated as follows: The Fifth Fleet thought that the withdrawal during inactive winter months of aircraft should be considered, and increasing only ground troops without taking adequate measures to retain the western Aleutians would increase supply, which would make rather be at the enemy's discretion [3, p169]. 

However, the Navy General Staff proposed as follows: Withdrawal would allow the enemy to construct air bases and advance further west, so the Japanese military should regain Attu Island and build airfields on Attu Island and Kiska Island by February of the following year [3, p170]. The idea was different from that of the Fifth Fleet, but it seems that the Fifth Fleet was convinced by the proposition of airfield construction by the Imperial General Staff [4, p359]. This was the third change in defense policy since landing.

The commander of the North Army Force was replaced by Vice Admiral Kiichiro Higuchi on August 1. He is also famous for having tens of thousands of Jews escape to Shanghai via Harbin in Manchuria when he was there. The North Army Force was not in charge of the Aleutian area at that time, but he had interests and raised the war plan for the area to the Imperial General Headquarters. For this reason, the Imperial General Headquarters dispatched a northern research team headed by Maj. Gen. Matsujiro Kimura to Kiska Island in September to collect information for defense. The debriefing session for the research team was held on October 26 at the Army General Staff Headquarters. The report of it properly suggested the important points, so I will summarize some of them [3, Appendix No,8] . 

Judgment of the situation in the direction of "Aleutian"

The enemy's invasion is most likely next spring and we needs to be prepared by next March.

The enemy's tactics is block of our long supply line for reduction our strength by direct bombing.

The invasion is unlikely to be surprise attacks, and they will reduce our strength through artillery fire and bombing and then will directly assault.

Setting of defensive zones 

Airfields are necessary for defense.

Amchitka Island is relatively flat, especially along the coast of Constantine Harbor. However, there are many swamps, so considerable construction efforts are required.

There are two sites suitable for airfield at the eastern end of Shemya Island.

Construction of a 100m x 800m runway on Kiska Island will take about 70,000 man-days.

Defensive facility

It seems cruel for soldiers to defend only with defense facilities without airfields. If so, the soldiers will only atrophy and become even more disadvantaged.

Hearing the results of the debate at this debriefing session, Major general Toichiro Mineki, the commander of North Sea Garrison (Hokkai Shubitai; details are described later), wondered the military's idea to complete both the airfield construction and the fortification by April-May next year. He also felt that there was a lack of consideration of the weather conditions on Attu Island in conducting various operations [3, p171].

5.3.2 Reoccupation of Attu Island

Abruptly, on October 18, the information came in that the Allied Forces had occupied Amchitka Island. This was a false alarm, but the cause is said to have been announced by US radio broadcasts [4, p364]. At the time, the policy of occupation of Attu Island again had already been decided, so the Imperial Army hurriedly ordered the North Army Force to reoccupy Attu Island (Great Army Ordinance No. 706) on October 20. 

Approximately 600 men, including the Northern-Kuril-Fortress Infantry extracted from the North Army Force, led by Lieutenant Colonel Hiroshi Yonekawa, were transported by three light cruisers, "Abukuma", "Tama", and "Kiso". They landed on Attu Island to reoccupy on October 29 [4, p347]. In addition, about 520 men of the anti-aircraft artillery unit gathered from the Western and Eastern Army Forces were reinforced to Attu Island on November 12 by the cargo vessels "Dou-baa (Dover) Maru" and "Dairin Maru" [3, p176].

In order to secure Kiska Island and Attu Island, the Imperial General Headquarters newly established the Army "North Sea Garrison" on Kiska Island on October 24, under the command of Maj. Gen. Juichiro Mineki, and put it under the command of the Fifth Fleet. The Imperial General Headquarters decided on November 1 the following "Army and Navy Central Agreement" [4, p366]:

・ Build a group of air bases consisting of Kiska Island, Attu Island, and Shemya Island by around February 1943.

・ Establish an air base for seaplane on Attu Island

・ The Army builds air bases and the Navy cooperates in transporting its materials

・ Advance fortress infantry to Attu Island

・ In the future, Amchitka Island may be occupied depending on the situation.

However, the last meant only postponing the occupation of Amchitka Island [3, p168]. The North Sea Detachment became the independent infantry battalion and entered under the North Sea Garrison. The newly established North Sea Garrison was provided with construction materials, telephones, dynamite for airfield construction, winter clothing, rain cloaks, rubber boots, etc. [3, p173].

On November 10, Army North Sea Garrison command, including the commander Maj. Gen. Juichiro Mineki, arrived on Kiska Island on the destroyers [4, p347]. The meeting was held with Maj. Gen. Katsumi Akiyama, commander of the Navy 51st Base Force, and the policy for strengthening defense was decided. It was confirmed that the Army would build the complex defense zone including the airfields on Kiska, Attu, and Shemya by the end of February, and that the necessary materials for this were needed to be transported by early December [3, p181]. At the meeting, it was argued that, without air superiority, the U.S. military would be activated after March next year, and that if the US military occupied Amchitka Island, it would be extremely difficult to defend Kiska Island.

The Japanese military had begun to strengthen the defense of the western Aleutian Islands in earnest. In accordance with the aforementioned Army and Navy Central Agreement, the transport of a large amount of materials and an operation to occupy Shemya Island near Attu Island were planned to be implemented by the end of December. However, since the US air force built the air base on Adak Island, Attu Island was also within the range of air raids from there. On November 6, "Kimikawa Maru" ferried five Navy Type 2 seaplane fighters and three reconnaissance seaplanes to Attu Island, but all of them became unusable on the next day due to the storm and the US air raids. The cargo ship "Cheribbon Maru", which arrived at Attu Island on November 27, was laid down by the low-altitude bombing by one B-24 bomber and four B-26 bombers [3, p187].

Navy Type 2 seaplane fighters in Holtz Bay, Attu Island. They seem to be in contact, probably due to strong winds. Taken from the US B-24 bomber.

https://ww2db.com/image.php?image_id=11832

The Shemya Island capture fleet, consisting of the light cruiser "Tama", the destroyer "Hatsushimo", and the army cargo ships "Montrile Maru" and "Yawata Maru", left Paramushir on November 24. However, it was judged difficult to land on Shemya Island due to seeing the damage of the "Cheribbon Maru" on Attu Island, so the occupation operation of Shemya Island was canceled on the November 28 [3, p187]. When the false alarm of the occupation of Amchitka Island by US troops, it was even said by some Japanese officials that if Amchitka Island could not be retaken, the defense policy in this area should be fundamentally reconsidered [3, p167]. However, since the cargo ship was damaged on Attu Island, the occupation of Shemya Island even near Attu Island was canceled. The neglect of Amchitka Island and the suspension of the occupation of Shemya Island became to bring the major crisis to the defense of Kiska and Attu Islands in next May.

(to be continued)

References are listed in "Reference" in the upper right-hand side.

4. Aleutian Operation (2) Invasions on Attu Island and Kiska Island

 4-1 Invasion on Attu Island

The Attu invasion troops arrived outside Holtz Bay (Hokkai Bay) on Attu Island on the night of June 7, and the North Sea Detachment aboard the transport ship "Kinugasa Maru" landed in thick fog at 0010 (almost dawn) on June 8 [3, p116]. The Japanese War History Series, Senshi Sosho "Army Operations of the Northeastern <1>" states that "Unexpected mountains overlaped and no battalion cannons were able to be carried. The map was inaccurate, and it was difficult to determine the direction in the fog, so the troops often went wrong ways" [3, p117].

Although it was June, there was still a lot of snow left, and the march was carried out while trampling on the snow [12]. The troops marched through the snow that remained on the steep terrain and occupied Chichagof Harbor (Atsuta Bay) at 0730. Eventually, 1143 men of the North Sea Detachment consisting of one infantry battalion (1st battalion of the 26th infantry regiment), one company of engineers (a company of the 7th engineer regiment), and the Navy Communications Corps landed [7, p18].

Imperial Army soldiers landed on Attu Island (June 8)
https://ww2db.com/image.php?image_id=18565

No American soldiers were stationed on Attu Island, and the Japanese protected 37 Aleuts and an American radio engineer and his wife by the Japanese War History Series, Senshi Sosho "Navy operations in the Northeastern" [4, p255]. According to the materials on the American side and "Kiska Senki", there were 42 Aleut people who lived on Attu Island [2, p37] [7, p412]. The radio engineer and his wife committed suicide, but her wife survived and was sent to Japan as a prisoner of war [7, p413]. She was the only American citizen who became prisoner of war during the World War II.

The Japanese troops set the border with the Aleut settlements and lived friendly with them [7, p414]. When the Japanese troops abandoned Attu Island at the end of August, they moved to Kiska Island with all of the Aleut. Eventually the Aleut were relocated from Kiska Island to Otaru in Hokkaido [7, p413]. However, many of them died in the unfamiliar Japanese climate, and only 24 Aleut were alive at the end of the war [2, p37].

When landing on Attu Island, it estimated to take one week to land supplies (three months' worth of food) from the transport ship "Kinugasa Maru", but the Northern Unit issued a return order to "Kinugasa Maru" on June 10, three days after landing [3, p119]. The reason for this is not written. There were no air raids on Attu Island, only a Catalina flying boat reconnaissance on June 12. The tanker "Nissan Maru," which was supplying fuel (coal) to Attu Island, had requested to call at Kiska Island on the June 10 to replenish aviation fuel to the island. It would lead her to be bombed at Kiska Bay.

4-2 Invasion on Kiska Island

The transport ships "Hakusan Maru" and "Kumagawa Maru" carrying the Kiska invasion troops arrived near Shiraito Bay, north of Kiska Bay, at 2227 on June 7, and the troops started landing. Eventually, 550 men of the Navy Third Special Landing Force, which consisted of 3 companies, an anti-aircraft artillery corps, a surveillance corps (radar staff), and support unit (accounting, medical affairs, and communications), and 750 men of the engineer corps landed [7, p17] [3, p130]. There was a US military meteorological station built on May 18, with 10 observers in the northwest of Kiska Bay. One of the observers was injured when they learned of the approach of the Japanese troops with a machine gun sound. They hurriedly burned the code, but two were taken as the war of prisoners. The remaining eight escaped. However, the wounds of the injured observer worsened, and all but one surrendered to the Japanese troops the next morning [2, p36]. The remaining one also surrendered later.

Soldiers of the Navy Third Special Land Force landed on Kiska Island (the middle of June 1942)

https://ww2db.com/image.php?image_id=18394

The occupation of both islands was extensively announced in Japan for the purpose of concealing the defeat of the Battle of Midway. Two fishermen from the Northern Kuril Islands had been also sent to Kiska Island as a fishing group for supplementary food supply. The waters near Kiska Island were blessed with marine products. In the summer, not only were large numbers of cods, flatfish, salmon, and sea urchins caught when fishing, but geese and ducks were also caught when hunting. The fishing group was fishing between air raids and storms, but it is unknown how long they were [7, p409].

A seaplane base was set up on Kiska Island by the special cruiser "Awata Maru". On June 8, Navy Type Zero reconnaissance seaplanes (Jake) were transported by the seaplane tender "Kimikawa Maru", and patrol flight was started by them. On June 9, six Navy Type 97 Large Flying Boat (Mavis) of the East Port Naval Air Corps Detachment and three submarine chasers for defense arrived. Furthermore, on June 15, the seaplanes were reinforced by the seaplane tender "Kamikawa Maru". As a result, the number of seaplanes was follows: Navy Type Zero reconnaissance seaplane was seven; Navy Type Zero Observation Seaplane (Pete) was four; and Navy Type-95 reconnaissance seaplanes (Dave) was two [4, p269]. 

However, unloading from two transport vessels did not proceed easily. From the June 12, bombing by the US Army Air Corps began, as will be described later. In addition, the pier built on the coast of Kiska Bay for landing using Daihatsu-class landing craft was damaged repeatedly by the waves. In addition, coastal to inland roads had to be opened to carry landing supplies [7, p40].

Navy Type Zero reconnaissance seaplanes (Jake)

https://ja.wikipedia.org/wiki/%E9%9B%B6%E5%BC%8F%E6%B0%B4%E4%B8%8A%E5%81%B5%E5%AF%9F%E6%A9%9F#/media/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:E13A-3s.jpg

4-3 US military responses to the Japanese invasions

The United States noticed on June 8 that the weather report on Kiska Island had stopped coming. On June 9, a patrol flying boat found that both islands were occupied by the Japanese troops by discovering the Japanese ships in Kiska Bay and tents built on Attu Island [2, p37]. Chester Nimitz, Commander in Chief of US Pacific Fleet, ordered the Task Force 16 including the aircraft carriers "Enterprise" and "Hornet" to attack the Japanese fleet off Kiska Island on June 8. Task Force 16 headed off Kiska Island. However, Nimitz learned that a radio broadcast from Tokyo was broadcasting that the Japanese had finished occupying Attu and Kiska islands. He stopped the attack on June 11 and recalled the fleet, fearing that Task Force 16 would be ambushed by the Japanese fleet [2, p37]. Since the Japanese Navy changed the code on May 28, the failure to read the Japanese military's plans after the Midway Operation might have also be related to the suspension of the attack.

Until then, the United States had only placed secondary operational value towards the Aleutian Islands. The Japanese may have intended to invade further east. The United States was forced to prepare for defense against the Aleutian Islands and raise the priority of the allocation of war resources. In order to stop the further invasion, the US military first adopted a strategy of exhausting and weakening the Japanese forces by bombing with aircraft and attacking with submarines. Air reconnaissance was frequent because there was little information about the climate and geography of the Aleutian area. Old maps were also pulled out, but those maps only showed the shape of the coastline [10, p73].

Upon learning of the Japanese landing, the US Navy dispatched a seaplane tender "Gillis" to Nazan Bay, Atka Island. Twenty Catalina flying boats were gathered there and intensively bombed on Kiska Island from June 12 to 15, with one pilot flying for 19.5 hours over a 24-hour period for example [2, p42]. Several PBY Catalina flying boats were irreparably damaged, but only one was shot down over Kiska Island.

Seaplane tender "Gillis" in January 1942

https://www.history.navy.mil/content/history/nhhc/our-collections/photography/numerical-list-of-images/nara-series/80-g/80-G-10000/80-G-13141.html

The Eleventh Air Force hastily gathered B-17 and B-24 bombers at Fort Glenn base from the continental United States, and began bombing Kiska Island on June 12. The runway, which was simply laid with iron plates on a soft swamp, waved like a mattress during the takeoff and landing of heavy bombers. As the first raid, on June 12, three B-24 bombers were launched from Fort Glenn base. Upon arriving at Kiska Island, Japanese ships in the bay were gathered under the umbrella of anti-aircraft fire for defense. 

The Japanese shot down a B-24 bomber operated by Captain Todd with anti-aircraft fire [2, p41], and the scene was captured by a Japanese press member on Kiska Island [Imperial Navy Announcement Movie (the last part of it)]. Subsequently, five Catalina flying boats launched from Nazan Bay on Atka Island bombed, and three crew members were killed in anti-aircraft fire. In addition, five B-17 bombers bombed [2, p41], which damaged the starboard front of the destroyer "Hibiki" that was on the alert at the entrance of Kiska Bay. The destroyer "Hibiki" miraculously left no one injured and returned to Kiska Bay towed by the destroyer "Akatsuki" [7, p68].

P-40 Warhawk fighters of the 18th Fighter Squadron escorting B-24 Liberator bombers of the 21st Bomb Squadron over the Aleutian Islands, Alaska, Jul 1943.

https://ww2db.com/image.php?image_id=27132

After that, the bombing of the US military continued as long as the weather allowed. With a round trip of 2500 km from Fort Glenn Air Base to Kiska Island, weather information near Kiska Island was essential for the US air force to carry out long-range bombing. Therefore, almost every morning, a large bomber was dispatched as a meteorological observer around Kiska Island and Attu Island to report the weather conditions [10, p38]. 

However, the weather conditions west of Attu Island were unknown, and due to variable weather and difficulty of weather forecasts, bombers often turned back on the way even if they sortied. Or, they sometimes bombed by guessing the position of the target by using Mount Kiska (Kiska Fuji), whose head was sticking out of the clouds, as a mark. Fortunately for the Japanese, the US air raids were only successful six times in June due to weather and other factors. In July, the US bombers made 15 sorties, seven of which turned back on the way due to the bad weather. [10, p39]

4-4 Actions of the Japanese military after occupations

On Kiska Island, a coastal fuel depot was bombed and the gasoline continued to burn for several days. The Japanese soldiers on Kiska Island were tense by the relentless air attacks. The soldiers believed that the Navy's flying boats had been bombing. So when they found the large US Army bomber on the ground which was shot down on June 12, they were surprised. They did not expect the large US Army bombers to arrive so soon after landing [7, p64]. 

These air raids were completely unexpected for the Japanese troops. The seaplanes deployed on Kiska Island had not ability to intercept large bombers, and the number of field anti-aircraft guns laid on the coast in a hurry was small, resulting in insufficient air defense capabilities. Therefore, as will be described later, Navy Type 2 seaplane fighters (Rufe), which had not been originally planned, would be deployed for air defense. 

On June 13, the captain of the light cruiser "Kiso" made an opinion to the Northern Unit that on board fighters should be dispatched for interception from the second Task Force over Kiska Island. However, the command of the second Task Force rejected it for confidentiality of the location of fleet [4, p262].

The type 97 Large Flying Boat deployed began patrol flight in mid-June, but during this period the crew had great difficulty in reconnaissance and water landing due to frequent fog. The top altitude of the fog was not high, and mountain peaks on islands often appeared above the fog. Therefore, when landing in the fog, the pilots remembered the topography of the island from the shape of the mountain and plunged into the fog using the same method as the night landing method [13, p204]. However, due to the high latitude, the compass was greatly displaced. Furthermore, after the front passed, the altimeter (barometer) set to zero at the ground pressure at the departure deviated significantly [10, p47].

Type 97 Large Flying Boat with bombs on its main wing

https://ja.wikipedia.org/wiki/%E4%B9%9D%E4%B8%83%E5%BC%8F%E9%A3%9B%E8%A1%8C%E8%89%87#/media/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:KawanishiH6K.jpg

On June 13, a seaplane reconnaissance aircraft of "Kimikawa Maru" found a seaplane tender and 11 flying boats in Nazan Bay, Atka Island. The Japanese attacked the seaplane tender on June 15 with five Type 97 Large Flying Boat [4, p269]. However, the attack was after the US seaplane tender and the flying boats had left on the night of June 14 due to the exhaustion [2, p42]. There is another view that the seaplane tender had been evacuated by receiving the information on the Japanese attack from the intelligence department in advance [3, p124].

The Japanese flying boats moored in Kiska Bay were exposed to the bombing by large US bombers. Therefore, from June 21 to 22, the large flying boats of the East Port Naval Air Corps Detachment were temporarily removed to Paramushir. The reconnaissance seaplanes also evacuated to Agattu Island except for the seaplanes for observation. 

Although they were re-deployed at Kiska Island on July 1, the flying boats of the Yokohama Naval Air Corps, deployed in Tulagi near Guadalcanal Island, were wiped out by the landing of the Allied Forces on August 7. All the large flying boats of the East Port Naval Air Corps were removed to Yokohama on August 14 for replenishment of the Yokohama Naval Air Corps [4, p296]. The reconnaissance seaplane unit left Kiska Island, including the seaplane fighters deployed in July, became the Fifth Air Corps on August 5 [4, p297].

Special seaplane tender "Kimikawa Maru" anchored in Ominato

https://commons.wikimedia.org/wiki/File:Kimikawa-maru_in_1943.jpg

On June 19, the oil tanker "Nissan Maru" was sunk in Kiska Bay by bombing of five B-24 bombers and three B-17 bombers. The military ships and two transport vessels moored in Kiska Bay left Kiska Bay on June 20 with the remaining materials loaded [4, p270]. The US air raids demonstrated their effects, leaving only three submarine chasers and Daihatsu-class landing crafts in Kiska Bay. Two of the submarine chasers were also sunk outside Kiska Bay on July 15 by the attack of the submarine, USS Grunion [4, p325].

Japanese transport ship in Kiska Bay burned by air raid on June 19 (probably "Nissan Maru")
https://www.history.navy.mil/our-collections/photography/numerical-list-of-images/nhhc-series/nh-series/80-G-11000/80-G-11686.html

4-5 Imperial Navy Intercept Operation for the U.S. Task Force 

On June 11, the Imperial General Headquarters issued a warning to the Combined Fleet and the Fifth Fleet, as the US Task Force may have headed for Kiska Island from intercepting radio messages [4, p258]. However, as mentioned above, on this day the US Task Force abandoned the attack and turned around. 

In preparation for the emergence of the US Task Force, the Northern Unit changed its standby area to 350 km southwest of Attu Island because of the discovery a seaplane tender on Atka Island on June 13 [4, p259]. On the same day, the Combined Fleet Command reinforced the Northern Unit with the aircraft carrier "Zuikaku", destroyers, and others, so the number of aircraft carriers in the Second Task Force became four [4, p260].  A total of nearly 80 Japanese ships had been operating in the area.

The US military sensed the existence of the large Japanese fleets and raised the sense of crisis that the entire Aleutian Islands might be invaded by the Japanese [8, p15]. The US Navy deployed old-fashioned S-class submarines of around 1000 tons in the northern Pacific Ocean to probe the movements of the Japanese fleet, but the navigation was difficult for this class of submarines in the rough seas near the sunken-rock-rich Aleutian Islands. On June 19, the submarine S-27 ran aground near Amchitka Island due to the bad weather. Her crew was rescued after drifting on the life rafts for six days [10, p46].

The commander of the Northern Unit made a plan to dispatched fighters from two aircraft carriers "Zuikaku" and "Zuiho" to over Kiska Island on June 20 to intercept large bombers. However, the plan was postponed to June 21 because of the forecast of bad weather on June 20. However, Combined Fleet Command opposed the operation which divided the air forces of Task Force, so ordered the Northern Unit to return to Ominato on June 20 to prepare for the next operation [4, p262]. Therefore, the dispatch plan of fighters over Kiska Island was not carried out after all. All ships of the Northern Unit, including reinforcements, had returned to Ominato and elsewhere by June 24.

Since the Japanese Navy changed the code at the end of May, the information of the US Military Intelligence Service at the time was confusing. The intelligence agency believed that the Japanese occupation of the western Aleutian Islands could be the beginning of a conquest of the entire North Pacific Ocean [2, p43].

On June 20, the US military intelligence service judged from the radar information that a large Japanese fleet including four aircraft carriers and two battleships was heading north in the Bering Sea toward Nome of Alaska. A large-scale airlift operation of soldiers and weapons was carried out over a two-week period from June 21 using more than 140 transport aircraft to defend Nome where there was no land road [2, p43]. As a result, an army unit of 2000 men was established in Nome in early July. Also, as if to support the invasion of the Japanese troops, the submarine "I-26" fired near Vancouver on June 20, and the submarine "I-25" fired at the US military base on the west coast of Oregon on June 22.

(To be continued)

References are listed in "Reference" in the upper right-hand side.