During World War II, , also called shimbu-tai, were specialized units of the Imperial Japanese Navy and Imperial Japanese Army normally used for suicide missions. They included kamikaze aircraft, fukuryu frogmen, and several types of suicide boats and submarines. Background Towards the end of the Pacific War, the Japanese were increasingly anticipating an American attack into the country and preparation was made for its defense. This was called Ketsu Go and the operation included the formation of specialized Japanese units. The move was driven by the realization that, in order to defend their homeland, conventional warfare was no longer sufficient. The recruitment of soldiers willing to die in the suicide missions was, therefore, easily carried out. The suicide attack is also an accepted method of fighting and this is largely attributed to Japan's highly militaristic society as demonstrated by the samurai system with its bushido code, which established a legacy that honors and idealizes self-sacrifice. Japan saw the efficacy of the specialized units during their deployment in the Philippines in summer-fall 1944 when special attack units executed their first missions. Japan saw that they were able to achieve results with limited resources. Historians view the success of the suicide tactics as an important driver to Japanese war policies after 1943. Aircraft Ohka suicide rocket aircraft The Yokosuka MXY-7 was a purpose-built kamikaze aircraft employed by the Imperial Japanese Navy Air Service towards the end of World War II. The US gave the aircraft the Japanese name Baka ("idiot"). It was a small flying bomb that was carried underneath a Mitsubishi G4M2e "Betty", Yokosuka P1Y Ginga "Frances" (guided Type 22) or planned Heavy Nakajima G8N Renzan "Rita" (transport type 33) bomber to within range of its target; on release, the pilot would first glide towards the target and when close enough he would fire the Ohkas engine(s) and dive onto the ship to destroy it. That final approach was almost unstoppable (especially for Type 11) because the aircraft gained tremendous speed. Later versions were designed to be launched from coastal air bases and caves, and even from submarines equipped with aircraft catapults, although none were actually used this way. Shinryu The Mizuno was a proposed rocket-powered kamikaze aircraft designed for the Imperial Japanese Navy towards the end of World War II. It never reached production. Tsurugi The Nakajima Ki-115 was a one-man kamikaze aircraft developed by the Imperial Japanese Army Air