Masakatsu Morita

was a Japanese political activist who killed himself via seppuku with Yukio Mishima in Tokyo.

Morita was the youngest child of the headmaster of an elementary school. Losing both parents at the age of three, Morita was cared for by his brother Osamu and educated at a Catholic school. He entered Waseda University in 1966, but was dismayed by the presence of Communist Zengakuren students at the university and became heavily involved in the small right-wing faction at the university. He first met Mishima on 19 June 1967, and joined the Tatenokai at its establishment in October 1968. As early as March of that year, he had written a letter to Mishima expressing a willingness to die for him.

Mishima was interested in using his society for direct political action, and he approached several members in April and May 1970. The inner circle then consisted of Mishima, Morita, and ("Chibi" Koga). No clear plan was developed until late June. Shortly afterwards, Mishima went on holiday to Shimoda and paid for the others to go to Hokkaido. On 2 September in Tokyo, Morita and "Chibi Koga" recruited ("Furu" Koga), who was a Tatenokai member also, and he met Mishima to hear details of the plan on 9 September.

Originally all four Tatenokai members had planned to commit seppuku along with Mishima. However, Mishima attempted to dissuade them and three of the members acquiesced to his wishes. Only Morita persisted, saying, "I can't let Mr. Mishima die alone." So, in November, Mishima ruled that only he and Morita were to die. Morita said to other members who had wanted to die together, "We are alive or dead together, because we can meet again somewhere." But Mishima knew that Morita had a girlfriend and still hoped he might live. On 21 and 22 November 1970, supplies were bought, and Morita asked Hiroyasu Koga to stand in for him if he should fail to behead Mishima properly. The next two days were spent rehearsing. (This is the survived member 's testimony.)