Take Ichi convoy

Unveiling the Take-Ichi Sendan: A Naval Convoy’s Tragic Fate

The Take-Ichi sendan, a Japanese naval convoy of World War II, left occupied Shanghai on April 17, 1944, carrying two infantry divisions to reinforce Japan’s defensive positions in the Philippines and western New Guinea. But what happened next? Why did this convoy face such a devastating fate?

The Strategic Importance and Tragic Losses

Imagine a convoy of ships, each one packed with soldiers ready for battle. The Take-Ichi sendan was no ordinary convoy; it carried the hopes and dreams of Japan’s military strategy in the Pacific theater. But on April 26 and May 6, 1944, this convoy faced an unexpected adversary: USN submarines. Four transports were sunk, and over 4,000 soldiers lost their lives. The question remains: why did such a significant loss occur?

Strategic Consequences

The losses from the Take-Ichi sendan had profound strategic consequences. Allied code breakers intercepted Japanese radio signals, guiding US submarines to ambush the convoy. This led to the decision by Japan’s Imperial General Headquarters to move its defensive perimeter back by 1,000 kilometers due to the failure of bringing these divisions to their destination without loss. The question is: how did such a critical piece of intelligence impact Japan’s strategic decisions?

Convoys and Anti-Submarine Doctrine

In September 1943, the Imperial Japanese Navy (IJN) and Army (IJA) agreed to establish defensive positions along the ‘absolute zone of national defense.’ However, shipping shortages delayed troop movements. Allied submarines were sinking large numbers of Japanese ships due to intercepted and decrypted radio transmissions. The IJN had a faulty anti-submarine doctrine, and convoys were not routinely assembled until 1943. The question is: why did it take so long for the IJN to implement effective convoy tactics?

The Take-Ichi Convoy

The Take-Ichi convoy was among several transport ships carrying reinforcements for the Marianas and Carolines that were sunk by Allied submarines during February 1944. The Grand Escort Fleet Headquarters increased the size of convoys from five to ten to twenty vessels, but this likely made them more vulnerable to submarine attack. The convoy was assembled in April 1944 at Shanghai, consisting of two divisions (32nd and 35th) bound for Mindanao and western New Guinea, respectively.

Attacks by US Submarines

The USS Jack sank one transport on April 26, 1944. The remaining ships continued to Manila before resuming their journey to New Guinea on May 1, 1944, with a changed destination for the 32nd Division. Allied code breakers detected the convoy’s departure and provided the Allies with its route, speed, daily positions, and destination. USS Gurnard attacked the convoy on May 6, sinking three transports. The rescue effort was successful, but 1,290 troops were killed, and much equipment was lost.

Strategic Withdrawal

The heavy losses led to the decision to dock in Halmahera instead of continuing to New Guinea. The surviving ships arrived on May 9 and sailed for Manila on May 13, arriving without further loss. The attacks blunted the 32nd and 35th Divisions’ fighting power, reducing their combat elements. The convoy’s failure assisted US Army general Douglas MacArthur’s double invasions of Hollandia and Aitape. The destruction also forced Japanese leadership to acknowledge that it was no longer possible to reinforce or defend western New Guinea.

Post-Convoy Analysis

The losses contributed to 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 1,000 km strategic withdrawal from the perimeter planned in March. Japanese naval staff officers gathered in Manila in June to analyze the Take-Ichi convoy. They believed that Japan’s communication codes were secure and discussed alternative explanations for the convoy’s detection. Explanations included an increase in radio signals, a Japanese officer accidentally divulging information, or Allied spies working on the Manila waterfront.

The meeting concluded that Allied spies were responsible for the convoy’s detection, and the Japanese military’s codes were not changed. Some surviving elements of the 32nd and 35th Divisions saw action against American forces after the withdrawal. The 35th Division was moved forward from Halmahera to Sorong in small ships during May. Elements of the 35th Division fought in battles on Biak, Sansapor, and Morotai, while most were stationed on the Vogelkop Peninsula. The 32nd Division was retained at Halmahera to garrison the island.

The Take-Ichi sendan stands as a stark reminder of the complexities and challenges faced by both sides during World War II. The strategic decisions, the intelligence operations, and the human cost all intertwine in this tragic tale. As we reflect on these events, it is crucial to understand not just the military strategies but also the broader implications for both Japan and the Allies.