Take Ichi convoy
Encyclopedia
The convoy was a Japanese
convoy
of World War II
. The convoy left Shanghai
on 17 April 1944, carrying two infantry
divisions
to reinforce Japan's defensive positions in the Philippines
and western New Guinea
. United States Navy
(USN) submarine
s attacked the convoy on 26 April and 6 May, sinking four transports and killing more than 4,000 soldiers. These losses caused the convoy to be diverted to Halmahera
, where the surviving soldiers and their equipment were unloaded.
The Take Ichi convoy's losses had important strategic results. The failure to bring the two divisions to their destination without loss contributed to the Japanese Imperial General Headquarters
' decision to move Japan's defensive perimeter back by 600 mi (965.6 km). The divisions' combat power was also blunted by their losses, and while they both saw action against United States Army
forces, they contributed little to Japan's attempt to defend its empire.
(IJN) and Imperial Japanese Army
(IJA) agreed to establish defensive positions along what was termed Japan's "absolute zone of national defense". The zone's perimeter reached from the Marianas Islands and Caroline Islands
to western New Guinea
and the Banda
and Flores Sea
s. At this time there were few Army units in the area, and it was decided to move combat units from China
and Manchuria
to protect the air bases which formed the basis of Japan's defensive plans. The movement of these troops was delayed by shipping shortages, however. Efforts to reinforce the Marianas and Caroline islands were assigned the highest priority, and the units selected for western New Guinea remained in China until April 1944, when ships became available to transport them.
By early 1944, Allied
submarines were sinking large numbers
of Japanese ships. Their activities were frequently guided by 'Ultra
' intelligence
relating to ship movements which was collected by intercepting and decrypting
encoded
radio transmissions. The IJN routinely broadcast the location and intended route of convoys under its protection, and decrypting these messages allowed Allied naval commanders to alert submarines in the vicinity of convoys. The submarine commanders were free to plan their interception and attack where conditions were most favorable.
The IJN's faulty anti-submarine
doctrine also contributed to Japan's shipping losses. The Navy had placed a low priority on protecting merchant shipping from submarine attack before and during the early years of the war and convoys were not routinely assembled until 1943. The Grand Escort Headquarters was formed in late 1943 to coordinate convoys and implement a standard doctrine. The Escort-of-Convoy headquarters was also established in April 1944 to provide a pool of senior commanders who were available to command convoys, though none had any experience with convoy operations or anti-submarine warfare.
Attacks on merchant shipping during February 1944 led the Japanese to change the composition of their convoys. During this month, over ten percent of the Japanese merchant marine was sunk by submarines and air attack. These losses included several transport ships carrying reinforcements to the Marianas and Carolines. In response, the Grand Escort Fleet Headquarters increased the average size of Japanese convoys from five ships to "large" convoys of 10-20 vessels. This change allowed the IJN to allocate more escort ships to each convoy and it was hoped that conducting fewer convoys would also reduce the number of targets available to submarines. While Japanese officers attributed a drop in sinkings during March to the changed tactics, this was actually due to the U.S. Pacific Fleet
's submarines being diverted to support raids conducted by the Fast Carrier Task Force
that month.
The Take Ichi convoy was assembled at Shanghai in April 1944. Its task was to carry the 32nd Division
to Mindanao
and the main body of the 35th Division to western New Guinea. Both divisions had been formed in 1939 and were veterans of fighting in China during the Second Sino-Japanese War
. One of the 35th Division's three infantry regiment
s was detached from the division in early April and sent to the Palau islands
, arriving there later that month without loss.
The two divisions embarked on large transport ships protected by an unusually strong escort force. Rear Admiral
Sadamichi Kajioka
—who was a veteran of several previous operations, including the Battle of Wake Island
—was appointed to command the convoy. The escort force was the newly established 6th Escort Convoy Command and included Kajiokia's flagship, the coal burning minelayer
, as well as destroyer
s , and , frigate
, ocean escort ships ('kaibokan') CD-20 and CD-22, minesweeper W-2, subchasers CH-37 and CH-38 and gunboat
s Uji, Ataka and Tama Maru No. 7.
The Take Ichi convoy sailed from Shanghai bound for Manila
on 17 April, and initially comprised 15 transports and the 6th Escort Convoy Command. Seven of the transports were traveling to Manila only and the 32nd and 35th Divisions were each carried by four vessels. Allied code breakers decrypted radio signals relating to the convoy's departure and subsequent intercepts allowed radio traffic analysts
to follow its progress south.
Intelligence from the intercepted radio signals was used to guide the submarine toward the convoy, and she made contact with it off the northwest coast of Luzon
on the morning of 26 April. The submarine's captain—Commander
Tommy Dykers—attempted to maneuver into a position to attack the convoy but lost contact when he was forced to evade a Japanese submarine. An aircraft sighted and attacked Jack a few minutes later, but the convoy did not change course. Dykers regained contact at midday after sighting Shiratakas heavy smoke exhaust and surfaced an hour before sunset to get into an attack position. He was forced to submerge, however, when another aircraft attacked the submarine.
Jack surfaced again after dark, and successfully attacked after the moon set. Dykers found that the Japanese escorts were alert, and was unable to penetrate the convoy. As a result, he attacked three times by firing a total of 19 torpedo
es from long range into the mass of ships at the center of the convoy. These attacks sank the 5,425-ton
freighter Yoshida Maru
, which was carrying an entire regiment of the 32nd Division. All 3,000 soldiers onboard drowned when the ship sank quickly. The remaining Japanese ships continued to Manila, arriving there on 29 April.
in western New Guinea and the eastern Netherlands East Indies
(NEI)—which were under direct threat of attack—rather than send it to Mindanao.
The Take Ichi convoy resumed its journey to New Guinea on 1 May. Its composition was now eight transports (one of the Manila-bound transports having replaced Yoshida Maru) under the protection of Shirataka, Asakaze, Shiratsuyu, minesweeper W-22, CH-37 and CH-38. The convoy took a special route planned by the Third Southern Expeditionary Fleet to reduce the risk of submarine attack.
U.S. signals intelligence operators again detected the convoy's departure. On 2 May, analysts estimated its size as nine transports and seven escorts carrying 12,784 troops of the 32nd Division and an unknown number of men from the 35th Division. Decoded Japanese Army Water Transport Code messages also provided the Allies with the convoy's route, speed, daily noon positions and destination. This "extraordinary intelligence coup" was passed to the relevant commands on 2 May and the USN positioned submarines to ambush the Japanese ships.
The Take Ichi convoy suffered a devastating submarine attack on 6 May. On that day, intercepted the Japanese ships in the Celebes Sea
near the northeastern tip of Celebes
. Gurnards captain—Commander Herb Andrews—submerged his boat and made a cautious approach to avoid detection by aircraft. He reached a firing position four hours later and fired six torpedoes at two transports. Only one of these torpedoes struck its mark, and a second salvo missed its intended targets but hit another transport. Andrews then turned his boat and fired further torpedoes from Gurnards stern torpedo tube
s which hit a third transport. One of the Japanese destroyers counterattacked Gurnard and forced Andrews to break off his attack. The destroyer was traveling at too great a speed for its detection gear to function, however, and did not damage the submarine, despite dropping approximately 100 depth charge
s.
Gurnard rose to periscope
depth two hours later and found that a major effort to rescue troops and equipment from the torpedoed transports was under way. That night, the submarine torpedoed one of the crippled transports which was still afloat. Gurnards attack sank transports Aden Maru (5,825 tons) and Taijima Maru (6,995 tons) as well as the cargo ship Tenshinzan Marau (6,886 tons). While the rescue effort was relatively successful, 1,290 troops were killed and much of their equipment was lost.
Due to its heavy losses, the Take Ichi convoy was ordered to dock at Halmahera in the eastern NEI rather than continue to New Guinea. The surviving ships arrived there on 9 May. Both divisions and their equipment were unloaded and the convoy sailed for Manila on 13 May, arriving on 20 May without further loss.
s and from four to one and a half artillery
battalions. Only four of the six 35th Division infantry battalions which sailed in the convoy reached Halmahera and much of the division's artillery was lost.
The destruction of the Take Ichi convoy also forced the Japanese leadership to acknowledge that it was no longer possible to reinforce or defend most of western New Guinea. While the Second Area Army
's commander Lieutenant General
Korechika Anami requested that the surviving ships attempt to carry the 35th Division to New Guinea, this was rejected by Imperial General Headquarters. The losses inflicted on the convoy also contributed to the Imperial General Headquarters' decision to move the perimeter of the "absolute zone of national defense" back to a line extending from Sorong to Halmahera. This represented a 600 mi (965.6 km) strategic withdrawal from the perimeter which had been planned in March.
Japanese naval staff officers gathered in Manila in June to analyze the Take Ichi convoy. The officers believed that Japan's communication codes were secure and discussed alternative explanations for the convoy's detection. These explanations included the increase in radio signals at the time the convoy sailed being detected by Allied radio traffic analysts, a Japanese officer in Manila accidentally divulging information and Allied spies working on the Manila waterfront radioing messages about the convoy's composition and departure. The meeting concluded that Allied spies were responsible for the convoy's detection, and the Japanese military's codes were not changed.
Some of the surviving elements of the 32nd and 35th divisions later saw action against American forces. The 35th Division was moved forward from Halmahera to Sorong in small ships during May. The regiment which had been sent to the Palaus in April was also successfully transferred to New Guinea. Elements of the 35th Division subsequently fought in the Battles of Biak
and Sansapor
, but most of the division was stationed on the Vogelkop Peninsula where it was isolated from September 1944. The 32nd Division was retained at Halmahera to garrison the island. Much of the division later saw action on the neighboring island of Morotai
, where it suffered heavy losses
while trying to counterattack an Allied force which had established a base there during September and October 1944.
Imperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
convoy
Convoy
A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support, though it may also be used in a non-military sense, for example when driving through remote areas.-Age of Sail:Naval...
of World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The convoy left Shanghai
Shanghai
Shanghai is the largest city by population in China and the largest city proper in the world. It is one of the four province-level municipalities in the People's Republic of China, with a total population of over 23 million as of 2010...
on 17 April 1944, carrying two infantry
Infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...
divisions
Division (military)
A division is a large military unit or formation usually consisting of between 10,000 and 20,000 soldiers. In most armies, a division is composed of several regiments or brigades, and in turn several divisions typically make up a corps...
to reinforce Japan's defensive positions in the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
and western New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
. United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
(USN) submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s attacked the convoy on 26 April and 6 May, sinking four transports and killing more than 4,000 soldiers. These losses caused the convoy to be diverted to Halmahera
Halmahera
Halmahera is the largest island in the Maluku Islands. It is part of the North Maluku province of Indonesia.Halmahera has a land area of 17,780 km² and a population in 1995 of 162,728...
, where the surviving soldiers and their equipment were unloaded.
The Take Ichi convoy's losses had important strategic results. The failure to bring the two divisions to their destination without loss contributed to the Japanese Imperial General Headquarters
Imperial General Headquarters
The as part of the Supreme War Council was established in 1893 to coordinate efforts between the Imperial Japanese Army and Imperial Japanese Navy during wartime...
' decision to move Japan's defensive perimeter back by 600 mi (965.6 km). The divisions' combat power was also blunted by their losses, and while they both saw action against United States Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
forces, they contributed little to Japan's attempt to defend its empire.
Background
In September 1943, the Imperial Japanese NavyImperial Japanese Navy
The Imperial Japanese Navy was the navy of the Empire of Japan from 1869 until 1947, when it was dissolved following Japan's constitutional renunciation of the use of force as a means of settling international disputes...
(IJN) and Imperial Japanese Army
Imperial Japanese Army
-Foundation:During the Meiji Restoration, the military forces loyal to the Emperor were samurai drawn primarily from the loyalist feudal domains of Satsuma and Chōshū...
(IJA) agreed to establish defensive positions along what was termed Japan's "absolute zone of national defense". The zone's perimeter reached from the Marianas Islands and Caroline Islands
Caroline Islands
The Caroline Islands are a widely scattered archipelago of tiny islands in the western Pacific Ocean, to the north of New Guinea. Politically they are divided between the Federated States of Micronesia in the eastern part of the group, and Palau at the extreme western end...
to western New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
and the Banda
Banda Sea
The Banda Sea is a sea in the Maluku Islands of Indonesia, technically part of the Pacific Ocean but separated from it by hundreds of islands, as well as the Halmahera and Ceram Seas...
and Flores Sea
Flores Sea
The Flores Sea covers 93,000 square miles of water in Indonesia.- Geography :The seas that border the Flores Sea are the Bali Sea , Java Sea , and the Banda Sea ....
s. At this time there were few Army units in the area, and it was decided to move combat units from China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
and Manchuria
Manchuria
Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People's Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast...
to protect the air bases which formed the basis of Japan's defensive plans. The movement of these troops was delayed by shipping shortages, however. Efforts to reinforce the Marianas and Caroline islands were assigned the highest priority, and the units selected for western New Guinea remained in China until April 1944, when ships became available to transport them.
By early 1944, Allied
Allies of World War II
The Allies of World War II were the countries that opposed the Axis powers during the Second World War . Former Axis states contributing to the Allied victory are not considered Allied states...
submarines were sinking large numbers
Allied submarines in the Pacific War
Allied submarines were used extensively during the Pacific War and were a key contributor to the defeat of the Empire of Japan. During the war, submarines of the United States Navy were responsible for 55% of Japan's merchant marine losses; other Allied navies added to the toll. The war against...
of Japanese ships. Their activities were frequently guided by 'Ultra
Ultra
Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by "breaking" high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School at Bletchley Park. "Ultra" eventually became the standard...
' intelligence
Intelligence (information gathering)
Intelligence assessment is the development of forecasts of behaviour or recommended courses of action to the leadership of an organization, based on a wide range of available information sources both overt and covert. Assessments are developed in response to requirements declared by the leadership...
relating to ship movements which was collected by intercepting and decrypting
Cryptanalysis
Cryptanalysis is the study of methods for obtaining the meaning of encrypted information, without access to the secret information that is normally required to do so. Typically, this involves knowing how the system works and finding a secret key...
encoded
Code (cryptography)
In cryptography, a code is a method used to transform a message into an obscured form, preventing those who do not possess special information, or key, required to apply the transform from understanding what is actually transmitted. The usual method is to use a codebook with a list of common...
radio transmissions. The IJN routinely broadcast the location and intended route of convoys under its protection, and decrypting these messages allowed Allied naval commanders to alert submarines in the vicinity of convoys. The submarine commanders were free to plan their interception and attack where conditions were most favorable.
Anti-submarine warfare
Anti-submarine warfare is a branch of naval warfare that uses surface warships, aircraft, or other submarines to find, track and deter, damage or destroy enemy submarines....
doctrine also contributed to Japan's shipping losses. The Navy had placed a low priority on protecting merchant shipping from submarine attack before and during the early years of the war and convoys were not routinely assembled until 1943. The Grand Escort Headquarters was formed in late 1943 to coordinate convoys and implement a standard doctrine. The Escort-of-Convoy headquarters was also established in April 1944 to provide a pool of senior commanders who were available to command convoys, though none had any experience with convoy operations or anti-submarine warfare.
Attacks on merchant shipping during February 1944 led the Japanese to change the composition of their convoys. During this month, over ten percent of the Japanese merchant marine was sunk by submarines and air attack. These losses included several transport ships carrying reinforcements to the Marianas and Carolines. In response, the Grand Escort Fleet Headquarters increased the average size of Japanese convoys from five ships to "large" convoys of 10-20 vessels. This change allowed the IJN to allocate more escort ships to each convoy and it was hoped that conducting fewer convoys would also reduce the number of targets available to submarines. While Japanese officers attributed a drop in sinkings during March to the changed tactics, this was actually due to the U.S. Pacific Fleet
United States Pacific Fleet
The United States Pacific Fleet is a Pacific Ocean theater-level component command of the United States Navy that provides naval resources under the operational control of the United States Pacific Command. Its home port is at Pearl Harbor Naval Base, Hawaii. It is commanded by Admiral Patrick M...
's submarines being diverted to support raids conducted by the Fast Carrier Task Force
Fast Carrier Task Force
The Fast Carrier Task Force was the main striking force of the United States Navy in the Pacific Ocean theatre of World War II.The Fast Carrier Task Force was known under two designations. The Navy made use of two sets of upper command structures for planning the upcoming operations...
that month.
The Take Ichi convoy was assembled at Shanghai in April 1944. Its task was to carry the 32nd Division
32nd Division (Imperial Japanese Army)
The Imperial Japanese Army's 32nd Division was an infantry division during World War II. The division was raised in February 1939 and was stationed in China from May 1939. In April 1944 it was deployed to Halmahera in the Netherlands East Indies and surrendered to the US Army in August...
to Mindanao
Mindanao
Mindanao is the second largest and easternmost island in the Philippines. It is also the name of one of the three island groups in the country, which consists of the island of Mindanao and smaller surrounding islands. The other two are Luzon and the Visayas. The island of Mindanao is called The...
and the main body of the 35th Division to western New Guinea. Both divisions had been formed in 1939 and were veterans of fighting in China during the Second Sino-Japanese War
Second Sino-Japanese War
The Second Sino-Japanese War was a military conflict fought primarily between the Republic of China and the Empire of Japan. From 1937 to 1941, China fought Japan with some economic help from Germany , the Soviet Union and the United States...
. One of the 35th Division's three infantry regiment
Regiment
A regiment is a major tactical military unit, composed of variable numbers of batteries, squadrons or battalions, commanded by a colonel or lieutenant colonel...
s was detached from the division in early April and sent to the Palau islands
Palau
Palau , officially the Republic of Palau , is an island nation in the Pacific Ocean, east of the Philippines and south of Tokyo. In 1978, after three decades as being part of the United Nations trusteeship, Palau chose independence instead of becoming part of the Federated States of Micronesia, a...
, arriving there later that month without loss.
The two divisions embarked on large transport ships protected by an unusually strong escort force. Rear Admiral
Rear Admiral
Rear admiral is a naval commissioned officer rank above that of a commodore and captain, and below that of a vice admiral. It is generally regarded as the lowest of the "admiral" ranks, which are also sometimes referred to as "flag officers" or "flag ranks"...
Sadamichi Kajioka
Sadamichi Kajioka
-Notes:...
—who was a veteran of several previous operations, including the Battle of Wake Island
Battle of Wake Island
The Battle of Wake Island began simultaneously with the Attack on Pearl Harbor and ended on 23 December 1941, with the surrender of the American forces to the Empire of Japan...
—was appointed to command the convoy. The escort force was the newly established 6th Escort Convoy Command and included Kajiokia's flagship, the coal burning minelayer
Minelayer
Minelaying is the act of deploying explosive mines. Historically this has been carried out by ships, submarines and aircraft. Additionally, since World War I the term minelayer refers specifically to a naval ship used for deploying naval mines...
, as well as destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...
s , and , frigate
Frigate
A frigate is any of several types of warship, the term having been used for ships of various sizes and roles over the last few centuries.In the 17th century, the term was used for any warship built for speed and maneuverability, the description often used being "frigate-built"...
, ocean escort ships ('kaibokan') CD-20 and CD-22, minesweeper W-2, subchasers CH-37 and CH-38 and gunboat
Gunboat
A gunboat is a naval watercraft designed for the express purpose of carrying one or more guns to bombard coastal targets, as opposed to those military craft designed for naval warfare, or for ferrying troops or supplies.-History:...
s Uji, Ataka and Tama Maru No. 7.
Shanghai to Manila
Manila
Manila is the capital of the Philippines. It is one of the sixteen cities forming Metro Manila.Manila is located on the eastern shores of Manila Bay and is bordered by Navotas and Caloocan to the north, Quezon City to the northeast, San Juan and Mandaluyong to the east, Makati on the southeast,...
on 17 April, and initially comprised 15 transports and the 6th Escort Convoy Command. Seven of the transports were traveling to Manila only and the 32nd and 35th Divisions were each carried by four vessels. Allied code breakers decrypted radio signals relating to the convoy's departure and subsequent intercepts allowed radio traffic analysts
Traffic analysis
Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. It can be performed even when the messages are encrypted and cannot be decrypted. In general, the greater the number of messages observed, or even intercepted and...
to follow its progress south.
Intelligence from the intercepted radio signals was used to guide the submarine toward the convoy, and she made contact with it off the northwest coast of Luzon
Luzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
on the morning of 26 April. The submarine's captain—Commander
Commander (United States)
In the United States, commander is a military rank that is also sometimes used as a military title, depending on the branch of service. It is also used as a rank or title in some organizations outside of the military, particularly in police and law enforcement.-Naval rank:In the United States...
Tommy Dykers—attempted to maneuver into a position to attack the convoy but lost contact when he was forced to evade a Japanese submarine. An aircraft sighted and attacked Jack a few minutes later, but the convoy did not change course. Dykers regained contact at midday after sighting Shiratakas heavy smoke exhaust and surfaced an hour before sunset to get into an attack position. He was forced to submerge, however, when another aircraft attacked the submarine.
Jack surfaced again after dark, and successfully attacked after the moon set. Dykers found that the Japanese escorts were alert, and was unable to penetrate the convoy. As a result, he attacked three times by firing a total of 19 torpedo
Torpedo
The modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...
es from long range into the mass of ships at the center of the convoy. These attacks sank the 5,425-ton
Gross Register Tonnage
Gross register tonnage a ship's total internal volume expressed in "register tons", one of which equals to a volume of . It is calculated from the total permanently enclosed capacity of the vessel. The ship's net register tonnage is obtained by reducing the volume of non-revenue-earning spaces i.e...
freighter Yoshida Maru
Yoshida Maru
The was a Japanese cargo ship owned by Nippon Yusen Kaisha. The ship was built in 1941 by Hakodate Dock at Hakodate on the northern island of Hokkaidō.-History:The Yoshida Maru was built at Hakodate; and she left port in August 1941 on her maiden voyage....
, which was carrying an entire regiment of the 32nd Division. All 3,000 soldiers onboard drowned when the ship sank quickly. The remaining Japanese ships continued to Manila, arriving there on 29 April.
Manila to Halmahera
The 32nd Division's destination changed during the voyage from Shanghai to Manila. Imperial General Headquarters was concerned that the increasing difficulty of shipping units towards the front line meant that it would not be possible to complete the planned reinforcement of the "absolute zone of national defense" before Allied forces reached the area. As a result, it was decided to use the division to reinforce the Second ArmyJapanese Second Army
The was an army of the Imperial Japanese Army. It was raised and demobilized on four separate occasions.-History:The Japanese 2nd Army was initially raised during the First Sino-Japanese War from September 27, 1894 to May 14, 1895 under the command of General Ōyama Iwao.It was revived for the...
in western New Guinea and the eastern Netherlands East Indies
Dutch East Indies
The Dutch East Indies was a Dutch colony that became modern Indonesia following World War II. It was formed from the nationalised colonies of the Dutch East India Company, which came under the administration of the Netherlands government in 1800....
(NEI)—which were under direct threat of attack—rather than send it to Mindanao.
U.S. signals intelligence operators again detected the convoy's departure. On 2 May, analysts estimated its size as nine transports and seven escorts carrying 12,784 troops of the 32nd Division and an unknown number of men from the 35th Division. Decoded Japanese Army Water Transport Code messages also provided the Allies with the convoy's route, speed, daily noon positions and destination. This "extraordinary intelligence coup" was passed to the relevant commands on 2 May and the USN positioned submarines to ambush the Japanese ships.
The Take Ichi convoy suffered a devastating submarine attack on 6 May. On that day, intercepted the Japanese ships in the Celebes Sea
Celebes Sea
The Celebes Sea of the western Pacific Ocean is bordered on the north by the Sulu Archipelago and Sulu Sea and Mindanao Island of the Philippines, on the east by the Sangihe Islands chain, on the south by Sulawesi, and on the west by Kalimantan in Indonesia...
near the northeastern tip of Celebes
Sulawesi
Sulawesi is one of the four larger Sunda Islands of Indonesia and is situated between Borneo and the Maluku Islands. In Indonesia, only Sumatra, Borneo, and Papua are larger in territory, and only Java and Sumatra have larger Indonesian populations.- Etymology :The Portuguese were the first to...
. Gurnards captain—Commander Herb Andrews—submerged his boat and made a cautious approach to avoid detection by aircraft. He reached a firing position four hours later and fired six torpedoes at two transports. Only one of these torpedoes struck its mark, and a second salvo missed its intended targets but hit another transport. Andrews then turned his boat and fired further torpedoes from Gurnards stern torpedo tube
Torpedo tube
A torpedo tube is a device for launching torpedoes. There are two main types of torpedo tube: underwater tubes fitted to submarines and some surface ships, and deck-mounted units installed aboard surface vessels...
s which hit a third transport. One of the Japanese destroyers counterattacked Gurnard and forced Andrews to break off his attack. The destroyer was traveling at too great a speed for its detection gear to function, however, and did not damage the submarine, despite dropping approximately 100 depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...
s.
Gurnard rose to periscope
Periscope
A periscope is an instrument for observation from a concealed position. In its simplest form it consists of a tube with mirrors at each end set parallel to each other at a 45-degree angle....
depth two hours later and found that a major effort to rescue troops and equipment from the torpedoed transports was under way. That night, the submarine torpedoed one of the crippled transports which was still afloat. Gurnards attack sank transports Aden Maru (5,825 tons) and Taijima Maru (6,995 tons) as well as the cargo ship Tenshinzan Marau (6,886 tons). While the rescue effort was relatively successful, 1,290 troops were killed and much of their equipment was lost.
Due to its heavy losses, the Take Ichi convoy was ordered to dock at Halmahera in the eastern NEI rather than continue to New Guinea. The surviving ships arrived there on 9 May. Both divisions and their equipment were unloaded and the convoy sailed for Manila on 13 May, arriving on 20 May without further loss.
Aftermath
The attacks on the Take Ichi convoy blunted the 32nd and 35th Divisions' fighting power. The 32nd Division's combat elements were reduced from nine to five infantry battalionBattalion
A battalion is a military unit of around 300–1,200 soldiers usually consisting of between two and seven companies and typically commanded by either a Lieutenant Colonel or a Colonel...
s and from four to one and a half artillery
Artillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...
battalions. Only four of the six 35th Division infantry battalions which sailed in the convoy reached Halmahera and much of the division's artillery was lost.
The destruction of the Take Ichi convoy also forced the Japanese leadership to acknowledge that it was no longer possible to reinforce or defend most of western New Guinea. While the Second Area Army
Japanese Second Area Army
The was a field army of the Imperial Japanese Army during World War II.-History:The Japanese 2nd Area Army was formed on July 4, 1942 under the control of the Kwangtung Army as a reserve and garrison force to maintain security and public order in Manchukuo...
's commander Lieutenant General
Lieutenant General
Lieutenant General is a military rank used in many countries. The rank traces its origins to the Middle Ages where the title of Lieutenant General was held by the second in command on the battlefield, who was normally subordinate to a Captain General....
Korechika Anami requested that the surviving ships attempt to carry the 35th Division to New Guinea, this was rejected by Imperial General Headquarters. The losses inflicted on the convoy also contributed to the Imperial General Headquarters' decision to move the perimeter of the "absolute zone of national defense" back to a line extending from Sorong to Halmahera. This represented a 600 mi (965.6 km) strategic withdrawal from the perimeter which had been planned in March.
Japanese naval staff officers gathered in Manila in June to analyze the Take Ichi convoy. The officers believed that Japan's communication codes were secure and discussed alternative explanations for the convoy's detection. These explanations included the increase in radio signals at the time the convoy sailed being detected by Allied radio traffic analysts, a Japanese officer in Manila accidentally divulging information and Allied spies working on the Manila waterfront radioing messages about the convoy's composition and departure. The meeting concluded that Allied spies were responsible for the convoy's detection, and the Japanese military's codes were not changed.
Some of the surviving elements of the 32nd and 35th divisions later saw action against American forces. The 35th Division was moved forward from Halmahera to Sorong in small ships during May. The regiment which had been sent to the Palaus in April was also successfully transferred to New Guinea. Elements of the 35th Division subsequently fought in the Battles of Biak
Battle of Biak
The Battle of Biak was part of the New Guinea campaign of World War II. It was fought between the United States Army and the Japanese Army from May 27 to June 22, 1944. It was the first major tactical use of an ambush by the Japanese during the war....
and Sansapor
Battle of Sansapor
The Battle of Sansapor was an amphibous landing and subsequent operations around Sansapor, Dutch New Guinea on the Vogelkop Peninsula during World War II....
, but most of the division was stationed on the Vogelkop Peninsula where it was isolated from September 1944. The 32nd Division was retained at Halmahera to garrison the island. Much of the division later saw action on the neighboring island of Morotai
Morotai
Morotai Island Regency is a regency of North Maluku province, Indonesia, located on Morotai Island. The population was 54,876 in 2007.-History:...
, where it suffered heavy losses
Battle of Morotai
The Battle of Morotai, part of the Pacific War, began on September 15, 1944, and continued until the war ended in August 1945. The fighting began when United States and Australian forces landed on the south-west corner of Morotai, a small island in the Netherlands East Indies , which the Allies...
while trying to counterattack an Allied force which had established a base there during September and October 1944.