Shinsaku Uesugi (上杉 晋作, Uesugi Shinsaku, born April 17, 1991 in Kyoto, Japan) is a Japanese chess player who holds the title of FIDE master. He won the 40th Japanese Chess Championship in May 2007 and became the youngest ever national champion (16 years, 18 days old). He also played for Japan at the 38th Chess Olympiad in November 2008 and became co-champion of the U.S. National High School Championship in April 2010.