Kaiten is the name of a type of Japanese human torpedoes from World War II. It can be assumed that the length of the Kaiten I (type I) torpedo was 14.75 meters, its maximum speed was up to 30 knots, and the maximum flight range did not exceed 75-80 kilometers. The warhead weighed up to 1,550 kilograms. The people responsible for creating this type of suicide were Sekiyo Nishina and Hiroshi Kuroki. The Japanese Navy approved the project in February 1944, and in September of the same year, the first base for the production and testing of Kaiten torpedoes was established. There were five types of Kaiten in total. The first four (Type 1, 2, 3 and 4) were structurally based on the 610 mm Type 93 torpedo, known as the "long spear". The fifth type - type 10 - was based on the type 92 torpedo of 533 mm caliber. A total of about 420 live Kaiten type torpedoes were built, most of which were Type 1s, with the Type 3 probably never making it past the design stage. Transportation of kaiten was carried out by specially adapted units of the Japanese fleet, most often submarines. The first combat use took place in November 1944, and Kaitens were used until the end of the war. However, this weapon proved ineffective, and one of its greatest successes was the sinking of the escort destroyer USS Underhill in July 1945.
