1. The Beginnings

1-1 Forgotten War

Here, the battles around Aleutian Islands refer to from the attack on Dutch Harbor by the Japanese Navy in June 1942 and the occupation of Attu Island and Kiska Island in the western Aleutian Islands, to the recapture of Kiska Island by the Allied Forces in August of the following year. These series of battles around the Aleutian Islands have received less attention than the main battlefields in the central Pacific. Of course, it is often talked about in each episode as "Dutch Harbor Attack", "Occupation of Attu Island and Kiska Island", "Sea Battle of the Komandorski Islands", "Gyokusai of the garrison of Attu Island", "Evacuation from Kiska Island", and "Allied invasion on unmanned Kiska Island". However, it is not always talked about throughout the all stories around Aleutian Islands and their relations. By looking at this blog, you might newly find other stories than the above episodes.

I am not a historian, but a scientist. The method employed here is the same as that used in scientific review papers. Most of the facts in this blog are described with the references. They are not my guesses and imaginations.

I do not know what kind of Japanese sources you (who cannot read Japanese) use to get information on what was going on in Japan during World War II. Official Japanese military records describing what happened during the war are limited. Long after the war, the Japanese government began collecting materials on the war, but many records had been scattered or burned at the end of the war. As a result, the official government archives consist of only a small portion of the remaining materials and testimonies of those who involved. However, their testimonies are not always consistent. This blog mainly uses the Japanese War History Series (Senshi-Sosho), the official Japanese government documents compiled by the Office of War History of Ministry of Defense. They are the primary and only "first-order" materials regarding the Japanese military activities during WWII. However, the Japanese War History Series are in an old writing style and contain expressions peculiar to the Imperial Navy and Army. Interpreting them is not easy even for contemporary Japanese people. However, I believe that I have adequately explained the acrtivities of Japanese military.

It is similar in the United States that the battles in Aleutian are not so respected, and the series of battles in Aleutian is also called "the forgotten war" [1]. Brian Harder, author of "Aleutian 1942-1943", states that American culture values clarity of purpose, decisive action, glamorous heroics, and easily romanticized imagery [2, p91]. And while there are plenty of suitable events in battles in the Central Pacific and Europe, less in battles in Aleutian which is often gloomy and foggy. These may be some of the reasons why they are also easily forgotten in the United States. This situation is similar in Japan.

The battles on Aleutian began two months earlier than the battle on Guadalcanal Island in the South Pacific, and ended with the Japanese evacuation from Kiska Island about half a year later than the battle on Guadalcanal Island. The battle on Guadalcanal Island, which began with the surprised invasion by the Allied forces (for Japanese), was a focused battle on airfield competition. By contrast, at the battles on Aleutian, there were few decisive and major land battles except for the battle on Attu Island. The Allied Forces gradually advanced westward through the Aleutian Islands, attacking the Japanese troops on Attu and Kiska Islands from the air and sea, and cutting their supply lines over a year. At that time, there was not much difference in strength between the US and Japanese forces. For that reason, the difference in the way of thinking about the war between the Japanese and US forces influecened the subsequent battles. Despite the fact that the battles in this theater could afford to take suficient time to consider the tactics, the Japanese could not avoid the annihilation on Attu Island and the evacuation from Kiska Island. What were the reasons?

The Aleutian Islands are located near the latitude of 50°N, and their climate is very different from that of the tropical central Pacific Ocean, which was the main battlefield between Japan and the United States. The enemy of these battles on Aleutian wasn't just the opponent forces. Soldiers from both the US and Japanese forces had to fight harsh climates and terrain, which also cost them a lot. The weather also had somehow influenced each of the above episodes. The battles on Aleutian were valuable examples of the impact of weather and climate on combat. The lessons from the series of battles on Aleutian also influenced the subsequent operations of World War II in the US military. Here, we will take a closer look at the course of the battle on Aleutian, including its relationship with weather and climate.

1-2 Alaska and Aleutian Islands

1.2.1 Geography

The Aleutian Islands, discovered by Danish-born Russian explorer Vitus Bering in 1741, span a 2000 km arc between Alaska and the Kamchatka Peninsula. The Aleutian Islands consist of about 120 volcanic islands, many of which have steep mountains of hard rock. The slightly higher mountains are covered with snow all year round. Plants rarely grow except shrubs. The few flatlands are covered with volcanic mud and are muddy marshes with a depth of nearly 1 m, and there are many places where it is not even easy to walk [2, p5]. The coves of the islands are intricately intricate and have many reefs, so care must be taken not to stranded when sailing nearby. Adak Island and Kiska Island have bays suitable as ports.

Kiska Island and Attu Island, where the battles in Aleutian were mainly happened, are located in the western part of the Aleutian Islands, which borders the North Pacific Ocean and the Bering Sea. Kiska Island is a volcanic island with a length of 35 km and a width of 8 km, with Kiska Fuji (elevation of 4000 feet) at the northern end, Kiska Bay on the east side of the central part of the island, and a slightly small Gertrude cove to the southwest. The middle part of the island was the only place where people could live, and the island was unmanned except for a few staff of the meteorological observatory in the US military. 

Attu Island is a rather large island with a length of 48 km and a width of 13 ~ 24 km. The cliffs that rise from the sea on the island are complex, with canyons sandwiched between snow-covered saw-toothed ridges at an altitude of about 1000 m. At the eastern end of the island is Chichagof Bay, where dozens of Aleut people lived. A radius of about 10 to 15 km to the west from that area was a place where people could act, and battles in the island were also held within that range.

Landscape of Chichagof Bay (1937).  The buildings of the locals can be seen in the rugged terrain.
https://www.loc.gov/pictures/item/2017872310/

1.2.2 History

Alaska, including the Aleutian Islands, was purchased by the United States from Russia in 1867. At that time, the purchase was described in the United States as the folly of the Secretary of State who attempted it [3, p92]. After that, a gold rush occurred in Alaska from the end of the 19th century, and the population increased. Formerly the District of Alaska, Alaska officially became the territory of the United States in 1912. In 1924, all people living in Alaska, including natives, were granted American citizenship.

Attu Island is the westernmost point of the American territory of the Aleutian Islands. Attu Island is about 1300 km from Dutch Harbor, where the US military was based, and about 1200 km from Paramushir, where the Japanese military was based. The Aleutian Islands and the Kuril Islands were kept as they were by the 1922 Washington Treaty, so neither Japan nor the United States could set up military facilities [3, p11]. The Washington Treaty expired in 1937, but the Aleutian Islands were largely defenseless until the beginning of World War II, both in Japan and the United States [2, p6]. The situation was almost the same for the Kuril Islands, which were Japanese territories.

1.2.3 Climate

The Aleutian Islands are far north of Japan, but the area around 53°N where Kiska Island and Attu Island are located is near Edmonton in Canada in the Americas and near Glasgow in the United Kingdom in Europe. The Gulf Stream, which is a warm current in the Atlantic Ocean, flows directly to high latitudes, so the western coast of Europe is relatively warm even at high latitudes. However, the Kuroshio Current, which is a warm current in the Pacific Ocean, turns east off the coast of Tohoku due to the influence of topography and the collision of the Oyashio Current (a cold current from the north), so the Aleutian Islands are not as warm as the same latitude on the west coast of Europe. The Kuroshio, which has turned around, gradually spreads northward and mixes with the cold seawater of the Bering Sea near the Aleutian Islands. Therefore, the atmosphere there often causes unstable weather such as fog and cloudy weather. Although it gets cold in winter, the sea around it does not freeze.

Monthly mean temperatures at Attu Island [4, p23]

The Aleutian Islands become a cyclone path which is called storm track that cyclones travel northeast through northern Japan with developing except in the summer. The developed cyclone often stagnates near the Aleutian Islands. In that case, while the winter-monsoon type pressure distribution of high west and low east continues in Japan, low clouds hung down and rough weather such as blizzard also continue in the Aleutian Islands. From the fact that Japan often has this winter-monsoon type pressure distribution in winter, it can be seen that the blizzards near the Aleutian Islands occur frequently during this season. Moreover, depending on the terrain, a strong local wind called williwaws may suddenly blow down from a steep mountain.

Although the climate is relatively mild in summer, it is known that fog frequently occurs in the waters of the Aleutian Islands due to the encounter of currents and air masses from the Arctic region with those from the Pacific Ocean. According to prewar data, the frequency of fog appearance was 18% in May, 26% in June, 57% in July, 38% in August, and 19% in September. There are two types of fog generation: around anticyclone and around low pressure. Fog around anticyclone often occurs and persists on the northwestern margin of the Pacific High. Fog around low pressure is generated as a cyclone approaches and dissipates as it passes [4, 25]. The unique weather of the Aleutian Islands is the cloudy weather and blizzards from autumn to winter and spring, the accompanying strong winds and high waves, and the frequent occurrence of summer fog.

1.2.4 Environment as a battlefield

Looking at the map, the route through the Aleutian Islands is the shortest great circle course from North America to Japan (or from Japan to North America). The Aleutian Islands, which are a series of many islands over a length of 1600 km, seem to have ideal conditions for invasion at first glance. Moreover, the Western Aleutian Islands were the only place where aircrafts with extended cruising range due to rapid development was able to directly bomb the Japanese territory (Kuril Islands) from the US territory.

However, the environment near the Aleutian Islands was very different from other battlefields. The weather near the Aleutian Islands was cold, with frequent strong winds and high waves, fog and clouds that caused frequent less visibility. The terrain consists of steep, snow-covered mountains, complex coastlines on many islands, bare and hard rocks with few trees, and a few flatlands covered with deep wetlands.

For ships, the few bays of the Aleutian Islands and the coast with many reefs were unsuitable as large berths and supply bases. Many obstacles such as high waves caused by strong winds, frequent fog, icing in winter, complex coastlines, and many sunken rocks made difficult for ships to navigate. For aircraft, sudden changes in the weather in the area, strong winds during takeoff and landing, variable visibility due to fog and clouds, and icing on wings were threats to safety. And for the soldiers, low temperatures and frequent winds and snow, difficult-to-walk mud swamps, cold, gloomy climates with little sunny weather, and frequent outbreaks of fog were harsh environments just to be there. In addition, the dampness caused by the frequent occurrence of fog often destabilized works of electronic devices such as communication devices.

Considering the usability of modern combat weapons by human soldiers, aircraft, ships and other precision machinery, Aleutian Islands are almost unsuitable for military activities. Moreover, both US and Japanese troops had little interest in such nature and weather in Aleutian Islands before the war.


1-3 Brief summary of battles around Aleutians

It may be painful to read through a long story of the battles at Aleutian, so I'll give you a brief summary here. If you keep this in mind, it may be easier to understand Chapter 2 and beyond. The title corresponds to the text.

Prewar situation

Japan started the war with the Allies by the attack on Pearl Harbor, but  the vast Pacific Ocean with no island spread over east of the Tohoku and Hokkaido regions of Japan. There was a possibility for Japan to receive a surprise attack by US fleets from there. The Imperial Navy Fifth Fleet, which was in charge of the defense of the sea north of Japan, felt the difficulty of defense. 

The Fith Fleet requested the Imperial General Headquarters to advance the patrol line using the western Aleutian Islands, which is the US territory. The Imperial General Headquarters also realized the danger of direct attaks on the Japan main land by the fact that the US made the air raids on Minamitorishima in March 1942. The Imperial General Headquarters intended to invade Attu Island and Kiska Island in western Aleutian Islands and to advance a patrol line using them in addition to Midway Island. The purpose of this invasion also included the prevention of the invasion on Japan via the Aleutian Islands by the Allied Forces. Therefore, the Imperial General Headquarters made the operation invading the western Aleutian Islands (AL Operation) in parallel with the Midway Operation that was also being planned.

However, the Imperial Army, which received the offer to participate in AL Operation, declined this. However, after the Doolittle air raid on Japan in April 18, the Army also felt the need to advance the patrol line, and changed its stance and agreed to participate in AL Operation capturing the western Aleutians. As a result, it was determined that Kiska Island was occupied by the Imperial Navy Third Special Landing Forces and Attu Island was occupied by the Imperial Army North Sea Detachment.

For the Japanese military, resistances by the US troops were expected during the invasion on Attu and Kiska. The US troops on Attu and Kiska would be supported by the US military base on Adak Island, which would be further supported by the large base in Dutch Harbor. Therefore, before occupying both islands, the attack plan was prepared to make the air raids on Adak Island and Dutch Harbor by the Japanese task force including two aircraft carriers during AL Operation in parallel with the Midway Operation.

The reconnaissance in the late May by the imperial Navy submarines and their onboard seaplanes found that there were no US troops on Attu and Kiska islands, and no military facilities on Adak Island. However, the Dutch Harbor attack plan was proceeded as it was, and the air raid date was set one day before the attack on Midway Island.

The full story of "Prewar situation" is here.

AL Operartion

On June 4, 1942, the Second Task Force, consisting of the aircraft carriers "Jun-yo" and "Ryujo", raided Dutch Harbor. However, due to the cloudy and foggy weather peculiar to this season, actually several torpedo bombers were only able to make bombing. Therefore, the Second Task Force changed the plan of the attack on Adak Island the next day, and air raided on Dutch Harbor again on June 5. On this day, the Second Task Force was attacked several times by the US bombers, B-17 and B-26, but fortunately for the Japanese, the Second Task Force did not suffer any damage. However, several Japanese dive bombers were shot down during the air raid by interception of US fighters launched from a secretly built air base west of Dutch Harbor. In addition, two dive bombers that lost their position due to dusk and fog could not return to their aircraft carrier and self-destructed on the sea. The discovery of the new airbase in the west of Dutch Harbor was reported to the Combined Fleet Command.

Also, during the attack on Dutch Harbor on June 5, a Navy type Zero fighter was hit by ground fire and crash landed on the wetlands on Akutan Island. The pilot died, and the aircraft was later requisitioned by the US military for performance testing. The elucidation of performance of Navy type Zero fighter by this requisition had great influences on the subsequent air battles.

Due to the failure of the Midway Operation on June 5, the AL Operation (landing operation) was temporarily canceled. However, despite that the advance of patrol line using three islands became impossible, the AL Operation resumed. The landings of Kiska Island and Attu Island from June 8 went successfully. Ten US military meteorological observers were taken as prisoners of war on Kiska Island. An US civilian couple, who were a communication engineer and a teacher, was also taken as prisoners of war on Attu Island. They had committed suicide, but the wife survived and became the only civilian prisoner of war during the war. About 40 Aluetes had lived friendly with the Japanese soldiers for a period of time, but they were taken to Japan via Kiska Island when the Japanese retreated from Attu Island in September.

The full story of "AL Operation (1)" is here.

The full story of "AL Operation (2)" is here.

The strengthen of defense of the western Aleutians

From June 12, the US military began the air raids on Kiska Island mainly using the long-range large bombers. This was an unexpected counterattack for the Japanese troops. The Japanese was forced to strengthen their defenses as the transport vessels being unloaded in Kiska Bay were damaged by bombing. The Imperial General Headquarters was determined to send Navy Type 2 seaplane fighters, Type A midget submarines (Kō-hyōteki), and additional cannons. During the transportation, three destroyers in the convoy were struck by torpedos from the US submarine outside the Kiska Bay. They sank and wrecked, but the transportation was successful.

The US Navy, which thought air strikes would be ineffective, planned a naval gunfire on Kiska Island. The implementation was delayed to August 8 due to fog. This was the day after the US military invaded on Guadalcanal Island in the South Pacific, but the gunfire on Kiska was not linked to it. The Japanese troops suffered little damage from this gunfire, but feared that the US forces might invade Kiska Island. Thus, the Imperial General Headquarters retreated Army troops in Attu Island and placed them on Kiska Island at the end of August, which strengthened the defense of Kiska Island. Many of the materials that had been transported on Attu Island were incinerated.

Meanwhile, the Allied troops landed on Adak Island, 400 km east of Kiska Island, at the end of August, completing a runway in only two weeks. Then, on September 15, the large-scale air raid by many bombers with fighter escort began. This made Kiska Island defense more difficult, and destroyers with fast speed were often used to transport supplies.

In response to this situation, the Fifth Fleet was considering withdrawal from the western Aleutians during the winter season. However, the Imperial General Headquarters insisted on continuing to secure there. They decided in October to reoccupy Attu Island, to build runways on Attu Island and Kiska Island by March, and to occupy Shemya Island east of Attu Island. Although the reoccupation of Attu Island was conducted successfully, the operation to occupy Shemya Island, which had began in November, was canceled due to the damage of the transport ship on Attu Island. The Japanese troops was also at a disadvantage in the battles on Guadalcanal Island in the South Pacific.

The full story of "The strengthen of defense of the western Aleutians" is here.

Winter in the Aleutian Islands

In the winter season, stormy weather and air raids made the transportation to Kiska and Attu Islands difficult. Moreover, in January 1943, the Allied troops occupied Amchitka Island, just 130 km east of Kiska Island, and began building an airfield there. The Japanese seaplanes bombed Amchitka Island several times from Kiska Island, but such the small air raids had little effect on the runway construction. The airfield on Amchitka Island was completed on February 18, and heavy air raids by the US air force were expected in the spring when the weather would be better. It was just when the Japanese troops evacuated from Guadalcanal Island.

The Imperial General Headquarters, which had felt the crisis, planned in February to carry out six transportations under the name of Operation "A-gou" in order to promote the construction of airfields and to strengthen the defense. However, on February 19, the US fleet made a naval gunfire on Attu Island. Furthermore, a transport ship engaged in the Operation "A-gou" was sunk on the way to Attu Island by gunfire of the US fleet. As a result, the other four transportations planned as Operation "A-gou" were canceled (One made successful). This cancellation made the shortage of supplies, which had a great impact especially on the defense of Attu Island. At that time, in the South Pacific, eight Japanese transport vessels and four destroyers sank on March 3 during the Battle of the Bismarck Sea, which also blocked the transportation to New Guinea.

The full story of "Winter in the Aleutian Islands" is here.

Battle of the Komandorski Islands and afterwards

The Fifth Fleet planned an "aggregate transport" to Attu and Kiska islands in March with the powerful escort ships consisting of cruisers and destroyers in order to exclude obstructions of the US fleet. The first aggregate transport was successful. On March 27, during the second transport, the Japanese fleet, consisting of two heavy cruisers, two light cruisers, and four destroyers, was encountered the US fleet consisting of a heavy cruiser, a light cruiser, and four destroyers southwest of Attu Island. At first, both the fleets made a mistake, but after that, the Japanese fleet chased the US fleet fleeing at high speed for a long time. The "Battle of the Komandorski" took place. The Japanese fleet was superior to the American fleet in terms of the number of ship and guns. Despite being in an advantageous position, however, the Japanese fleet steered away from the battlefield without giving decisive damages to the US fleet. The aggregate transport was also canceled.

After this, the transports to Kiska Island and Attu Island were carried out using only submarines. The airfield on Kiska Island is expected to be completed in comming May. From around May, the Aleutian Islands will be in a foggy season. In April, the Imperial General Headquarters considered transporting supplies for half a year in bulk during the foggy season. During the consideration, although the invasion by the Allied forces in the following spring was expected in the last fall, any responses to the expected invasion of the Allied forces was, mysteriously, not considered at all.

The full story of "Battle of the Komandorski Islands and afterwards" is here.

Allied forces landing on Attu Island

The Allied Forces suddenly invaded on Attu Island, which is closer to Japan than Kiska Island, in the fog on May 12. The Imperial General Headquarters were startled to hear this. The garrison of Attu had been wary of invasion from the first of May for a week at their own discretion, but the Allied invasion was shortly after the alert was lifted. The SG radar using microwaves allowed the Allied Forces to land in the fog.

Not having expected the invasion, the Imperial General Headquarters took time to respond. The Attu's garrison was building the airfield after the reoccupation in November, postponing the construction of defense facilities. In addition, the shortage of supplies due to cutting off by the Allied Forces made it difficult to complete the defense facilities. The Attu’s garrison stubbornly resisted. However, when the fog cleared, the defense bases were destroyed one after another by naval gunfires from battleships and the pinpoint attacks by aircraft. This gradually put the Attu’s garrison at a disadvantage.

The Attu's garrison retreated from the airfield under construction on May 18. The Imperial General Headquarters, which was planning a counterattack, gave up the rescue of Attu Island on May 20 and also decided to evacuate from Kiska Island. It was only about a week after the Allied Forces' invasion. The US military did not use the airfield under construction by the Japanese army, but built a new airfield at a different location later.

The Northern Forces sent a telegram to the Attu's garrison on May 20 in honor of its future annihilation. They continued to resist stubbornly, but were out of food. The Attu's garrison made numerous assaults on the night of the May 29. Although some broke through the front lines of the Allied Forces, the Allied Forces including the reserves counterattacked, and the Attu's garrison was wiped out. It is believed that many soldiers also committed suicide at that time. The annihilation of the Attu's garrison was reported to be "Gyokusai" in Japan, making it the first Gyokusai during the Pacific War.

The full story of "Allied forces landing on Attu Island" is here.

Evacuation from Kiska Island – “Ke-gou” Operation

After the smashing of Attu Island, Kiska Island was blocked from east and west by the Allied forces of Attu Island and Amchitka Island. Therefore, the withdrawal of the Kiska's garrison using submarines, called "Ke-gou" Operation, began on May 29 (first evacuation). Kiska Island had 5,600 people of the garrison, but a submarine could contain only 60 to 80 people at a time, and it was expected to take until September to evacuate all troops by submarine. 

Even so, it progressed smoothly at the beginning, and by June 18, about 870 people had successfully evacuated. However, from mid-June, after the occupation of Attu Island, the surveillance of the Allied blockade was strengthened. Submarines at that time could not travel long distances being submerged in the sea, and their transfer was exclusively by surface navigation. The several submarines sailing at sea surface were sunk in the fog one after another by firing using radar from Allied destroyers. As a result, the "Ke-gou" Operation was temporarily suspended.

The Combined Fleet had decided on the second withdrawal, which was intended to be withdrawn at once using ships. But this was a bet. The Japanese fleet could avoid air strikes when fog came out, but due to its inferior radar performance, it was more likely to be fired using radar from US military vessels. Moreover, if the fog cleared, there was no way to escape from air strikes. The Japanese fleet for evacuation was organized using the light cruisers and the destroyers belonged to the First Destroyer Squadron instead of transport vessels to minimize the time spent within the enemy attack area.

The fleet for evacuation, which had predicted the appearance of fog near Kiska Island, left Paramushir in the north Kuril Islands on July 7. The fleet stayed outside the US military's attack area for several days and waited for the opportunity that the area around Kiska Island was likely to become foggy. Once they rushed into Kiska Island, but the stable fog did not appear, and the fuel was running out. Therefore, Maj. Gen. Masatomi Kimura, the commander of the Destroyer Squadron, ordered their return.

This return was unavoidable, but the Imperial General Headquarters and the Fifth Fleet command were skeptical for the Destroyer Squadron's decision. For the next evacuation operation, the Fifth Fleet Commander-in-Chief was decided to accompany by the light cruiser "Tama" halfway for decision making. The second evacuation took place on July 22. This time the fog was deep on the way, so part of the fleet went missing in the fog and some of the ships collided with each other. Due to the possibility of thin fog on Kiska Island, after all, the accompanying Commander-in-Chief of the Fifth Fleet hesitated to decide to head for Kiska Island. Due to the push of the surroundings, the order to rush into Kiska Island was issued on July 28. Because of the deep fog on July 29, the evacuation was successfully carried out on Kiska Island. The fleet accommodated all the soldiers in Kiska Island in less than an hour and headed for Paramushir.

On this day, on July 29, the US fleet was temporarily away from the vicinity of Kiska Island. The powerful US fleet, including battleships, bombarded a phantom opponent on the night of the July 27 with the mysterious radar reactions, and was replenishing on July 29 at sea away from Kiska Island. The Japanese fleet encountered an US surfacing submarine in the fog on the way back, but the submarine seemed to misidentify it as a US fleet. The fleet returned safely to Paramushir from July 31 to August 1. In this way, the remaining 5186 soldiers miraculously succeeded in evacuating from Kiska Island.

The full story of "Evacuation from Kiska Island" is here.

Allied forces landing on Kiska Island

After the elaborate naval fires and bombardments, about 35,000 Allied troops landed in the fog on Kiska Island on August 16. Believing that the strong Japanese troops continued to defend Kiska Island, the Allied troops were killed and injured by friendly fire in the fog and land mines set by the Japanese troops. The Allies finally declared the occupation of Kiska Island on August 23. The US military built an air base on Attu Island and made several small bombings on the northern Kuril Islands, but they did not use it as the base to invade northern Japan.

(To be continued)

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