Kokichi Tsuburaya ran the 10,000 meters on the first day and the marathon on the last day in the 1964 Tokyo Olympics. He ran both races aggressively. He was with the lead group of Mills (14:04.6), Clarke, Wolde and Gammoudi at the half way point of the 10K. That was world record (28:15:6 by Ron Clarke) pace. Tsuburaya was the first to lose contact in the second half. He finished 6th in 28.59.4.
According to my notes in my Official Programme, Tsuburaya was 4th at the half way point in the marathon in 1:06.19. He was the second runner to enter the stadium but was passed by Basil Heatley in the last 100 yards. Tsuburaya's third place time was 2:16.22.8 which was his best time.
Three years later Tsuburaya had fallen on hard times due to injuries and I understand lumbago. Saying that he could no longer run, he committed suicide in a hotel on January 9,1968.