Seiichiro Sasaki

{{short description|Japanese long-distance runner}}

{{Use dmy dates|date=May 2020}}

{{Infobox sportsperson

| name = Seiichiro Sasaki

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| nationality = Japanese

| sport = Long-distance running

| event = Marathon

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| birth_date = {{birth date and age|1945|9|2|df=yes}}

| birth_place = Saga, Japan

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{{Nihongo|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.{{cite Sports-Reference |url=https://www.sports-reference.com/olympics/athletes/sa/seiichiro-sasaki-1.html |archive-url=https://web.archive.org/web/20200417211406/https://www.sports-reference.com/olympics/athletes/sa/seiichiro-sasaki-1.html |url-status=dead |archive-date=17 April 2020 |title=Seiichiro Sasaki Olympic Results |accessdate=6 May 2017}}

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.{{cite web|url=https://worldathletics.org/news/news/marathon-part-2-1967|title=The 1967 Fukuoka Marathon|website=worldathletics.org|access-date=September 13, 2022}}