Seiichiro Sasaki (佐々木 精一郎, Sasaki Seiichirō; born 2 September 1945) is a Japanese long-distance runner. He competed in the marathon at the 1968 Summer Olympics. Sasaki achieved a personal best in the marathon of 2:11:17, set in the 1967 Fukuoka Marathon, finishing second behind Derek Clayton, who ran 2:09:36.4, a world record for the marathon distance at that time. Sasaki's performance in this marathon was the second fastest in history up to that time.
Source: “Seiichiro Sasaki”, English Wikipedia (CC BY-SA 4.0), excerpt