Kōkichi Tsuburaya(円谷 幸吉,Tsuburaya Kōkichi?) (born Kokichi Tsumuraya(円谷 幸吉,Tsumuraya Kōkichi?); May 13, 1940 – January 9, 1968, Sukagawa, Fukushima) was a Japanese athlete who competed mainly in the Marathon.
Shortly after the Tokyo Olympics, Kokichi suffered from an ongoing back problem, known as lumbago. On January 9, 1968, he committed suicide by slashing his wrist in his dormitory room where he had stayed during his training period for the Mexico City Olympics. In his suicide note, he paid thanks to his parents, siblings and trainers for their contributions, urged his fellow runners to do well, and ended the note (please note this is informal translation): "I am too exhausted to run any more. Please forgive me. I'm sorry for causing my parents concern and worry, but this is for the best. Thank you very much for everything you have done for me." He was twenty-seven years old.