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Japanese Shin'yō suicide motorboat, 1945

A Shin'yō under way, being tested by Lt Col James F. Doyle USA commanding officer 2nd Bn. 305th Inf. 77th Div.

The Shin'yō (震洋?, "Sea Quake") were Japanese suicide motorboats developed during World War II. They were part of the wider Japanese Special Attack Units program.


Towards the end of 1943 in response to unfavorable progress in the war the Japanese command heard suggestions for various suicide craft. These suggestions were initially rejected but later deemed necessary.[1] For the naval department this meant kamikaze planes, kaiten submarines, fukuryu suicide divers or human mines and shinyo suicide boats.


These fast motorboats were driven by one man, to speeds of around 30 knots. They were typically equipped with a bow-mounted charge of up to 700 pounds of explosives that could be detonated by either impact or from a manual switch in the drivers area. These attack boats also carried two anti-ship rockets mounted on launchers located on either side of the boat behind the driver.

The similar Maru-ni, which were used by the Imperial Japanese Army, were equipped with two depth charges, and were not actually suicide boats, as the idea was to drop the depth charges and then turn around before the explosion took place. Although the chances of boat and crew surviving the wave from the explosion might seem slim, a small number of crewmen successfully escaped.[2] The depth charges used were known as the Experimental Manufacture Use 120 Kg . Depth Charge, and were armed by a delayed-action pull igniter.

Approximately 6,200 Shin'yō were produced for the Imperial Japanese Navy and 3,000 Maru-ni for the Imperial Japanese Army.[3] Around 400 boats were transported to Okinawa and Formosa, and the rest were stored on the coast of Japan for the ultimate defense against the expected invasion of the Home islands. The main operative use took place during the Philippines Campaign (1944–45).

Operational results

  • January 10, 1945: Sinking of American ships USS LCI(G)-365 (Landing Craft Infantry - Gunboat), USS LCI(M)-974 (Landing Craft Infantry - Mortar) and crippling of USS War Hawk (an auxiliary transport) in Lingayen Gulf, Luzon, Philippines.
  • January 31, 1945: Sinking of USS PC-1129 (Submarine chaser) off Nasugbu in Luzon, Philippines.
  • February 16, 1945. Sinking of USS LCS(L)-7 (Landing Craft Support - Large), LCS(L)-26, and LCS(L)-49 off Mariveles, Corregidor Channel, Luzon.
  • April 4, 1945. Sinking of USS LCI(G)-82 (Landing Craft Infantry - Gunboat) and USS LSM-12 (Landing Ship Medium) off Okinawa.
  • April 27, 1945. Crippling of USS Hutchins (DD-476) in Buckner Bay, Okinawa.



  1. Japanese suicide craft. US Navy. 1946. 
  2. Morison, Samuel Eliot (1959). History of United States Naval Operations in World War II: The Liberation of the Philippines. University of Illinois Press. pp. 138–140. ISBN 0-252-07064-X. 
  3. Japanese Suicide Weapons

External links

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