Japanese landing craft carrier Akitsu Maru

Lore & Background

Akitsu Maru was fitted with a full-length flight deck above the hull but lacked a hangar; aircraft were stored on the original main deck below. Conventional aircraft could take off from the deck but could not land due to the absence of landing mechanisms. In July 1944, KX arresting gear was installed, allowing the Kokusai Ki-76 liaison aircraft and the Kayaba Ka-1 autogyro to land on the short deck, the latter being able to do so without assistance.

Reader's Guide

Akitsu Maru represents a notable step in the evolution of amphibious warfare, combining the roles of aircraft carrier and landing craft carrier. Its design, influenced by the earlier Shinshū Maru, allowed it to carry 27 Daihatsu-class landing craft in a floodable well deck and discharge vehicles directly onto a pier. The ship's sinking on 15 November 1944, with the loss of 2,046 men—mainly from the Imperial Japanese Army's 64th Infantry Regiment—and 104 explosive motorboats, underscores the high cost of naval operations in the Korean Strait. The ship's legacy is complicated by the dispute over whether it or Shinshū Maru deserves the title of first amphibious assault ship, a debate that highlights the incremental development of Japanese amphibious capabilities during the interwar and wartime periods.

Did You Know?

• Akitsu Maru was originally a passenger liner taken over by the Imperial Japanese Army before completion.
• The ship carried 27 Daihatsu-class landing craft, but contrary to some claims, they were not stored in a floodable well deck; instead, they were carried on deck and launched by davits or cranes.
• On 15 November 1944, Akitsu Maru was torpedoed by USS Queenfish; a torpedo set off her aft magazine holding depth charges, causing her to sink.
• The Kokusai Ki-76 and Kayaba Ka-1 autogyro could land on Akitsu Maru's deck after KX arresting gear was fitted in July 1944.

Design & Engineering Innovation

Akitsu Maru represented a bold fusion of naval architecture and aviation capability. Built as a Type C landing craft carrier for the Imperial Japanese Army, she was originally conceived as a passenger liner before the IJA took possession prior to her completion. Her most striking feature was a full-length flight deck mounted above the hull, allowing conventional aircraft to take off from her surface. However, the absence of a hangar meant that planes were stowed below on the original main deck. The ship's amphibious facilities were equally remarkable: a floodable well deck carried 27 Daihatsu-class landing craft that could be released through an open stern gate, while davits held additional craft. Perhaps most impressively, a deck-level parking garage enabled vehicles to be driven directly onto a pier. In July 1944, KX arresting gear was retrofitted, enabling the small Kokusai Ki-76 liaison plane and the Kayaba Ka-1 autogyro to make landings on her short deck—capabilities that had no real parallel in Allied amphibious design at the time.

Pioneering Amphibious Warfare

The legacy of Akitsu Maru extends well beyond her brief wartime service. Alongside her sister Nigitsu Maru, she is frequently cited in naval literature as one of the earliest purpose-built amphibious assault ships in history. That claim, however, is contested by the earlier Shinshū Maru, an 8,000-tonne vessel that served a comparable role and actually served as the design template from which Akitsu Maru was refined. In 1937, British and American military observers witnessed Shinshū Maru conducting operations off Shanghai and immediately recognized the significance of what they saw—a new paradigm in projecting ground forces ashore under air cover. The Shinshū Maru carried two aircraft catapults and could transport and unload aircraft, a capability that Akitsu Maru expanded with her short take-off flight deck. Together, these two vessels gave the Japanese amphibious forces a complete prototype family of all-purpose assault ships, a concept that would not be matched by Western navies for years.

Training & Operational Role

Although Akitsu Maru was designed to provide air cover during amphibious landings, her actual wartime function was far more modest—essentially that of an aircraft ferry. Nevertheless, she played a meaningful part in the IJA's expanding aviation program. In mid-to-late 1943, the IJA Shipping Section simultaneously grew its anti-submarine personnel and developed the concept of carrier-based anti-submarine patrol aircraft. By the end of that year, twenty special pilot trainee officers entered the Shimosizu Army Air School. Their curriculum progressed from basic flight training on elementary aircraft, through familiarization flights in the Ki-76 liaison plane, and finally into dedicated anti-submarine patrol exercises. The ship's aviation facilities, including the later addition of KX arresting gear, supported this training pipeline by allowing small, slow aircraft like the Ki-76 and the Ka-1 autogyro to operate from her deck. In practice, Akitsu Maru served as a floating training and transport platform rather than the combat air-cover ship her designers had envisioned.

The Final Voyage

Akitsu Maru's career ended abruptly on 15 November 1944. The ship had departed for Singapore on 14 November as part of Convoy HI-81, a routine movement that would prove fatal. The following day, the American submarine USS Queenfish struck the convoy, and one of her torpedoes detonated Akitsu Maru's aft magazine, which was loaded with depth charges. The resulting explosion tore apart the stern of the vessel. As seawater surged into the engine rooms, the boilers ruptured in a secondary series of blasts, and the ship foundered in the Korean Strait at coordinates 33°17′N 128°11′E. The human cost was staggering: 2,046 men perished, the majority belonging to the Imperial Japanese Army's 64th Infantry Regiment, including the unit's commander. One hundred and four Maru-ni explosive motorboats also went to the bottom with the ship. Escort vessels managed to pull 310 survivors from the water, a small fraction of those aboard.

Gallery