is a retired long-distance runner from Japan, who represented his native country at the 1984 Summer Olympics in Los Angeles, California.
So won the 1976 edition of the Koà ¡ice Peace Marathon in Czechoslovakia. His twin brother is also a retired Olympic marathoner.
In 1984, So represented Japan at the 1984 Summer Olympics in Los Angeles, where he finished just outside the medals in fourth place.
He trained 2016 Olympics marathon runner Satoru Sasaki and runs the marathon program for the Japan Association of Athletics Federations.
His PR in the marathon was 2:08:55 at the 1983 Tokyo Marathon, finishing second, 17 seconds behind fellow Japanese runner Toshihiko Seko.