1 minelayer 3 destroyers 2 kaibokan escort ships 1 minesweeper 2 subchasers 3 gunboats The Take-Ichi sendan (Japanese: 竹一船団, lit.

The convoy left occupied 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) submarines attacked the convoy on 26 April and 6 May, sinking four transports and killing more than 4,000 soldiers.

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 1,000 km (600 mi).

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 war effort.

Their activities were frequently guided by "Magic" intelligence relating to ship movements which was collected by intercepting and decrypting encoded radio transmissions.

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.

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.

[2][19] Intelligence from the intercepted radio signals was used to guide the submarine USS Jack toward the convoy, and she made contact with it off the northwest coast of Luzon on the morning of 26 April.

Dykers regained contact at midday after sighting Shirataka's heavy smoke exhaust and surfaced an hour before sunset to get into an attack position.

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 Army in western New Guinea and the eastern Netherlands East Indies (NEI)—which were under direct threat of attack—rather than send it to Mindanao.

Decoded Japanese Army Water Transport Code messages also provided the Allies with the convoy's route, speed, daily noon positions and destination.

[20] The destroyer was traveling at too great a speed for her detection gear to function, however, and did not damage the submarine, despite dropping approximately 100 depth charges.

[20][23] 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.

[21] The loss of the Take Ichi convoy greatly assisted U.S. Army general, Douglas MacArthur's, double invasions of Hollandia and Aitape on 22 April 1944, hundreds of kilometers to the west of the previous battle line in eastern New Guinea.

MacArthur's forces were able to rapidly advance westward with minimal casualties within the next five months all the way to Morotai, just a short distance from Halmahera, partly as a result of the failure by these Japanese troops to be able to reach most of western New Guinea.

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.

[27] 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.