Yrjö Rantanen is a Finnish chess Grandmaster born on 27 April 1950. He is also a chess author and has written multiple books on the game, including "The Modern Benoni" and "Winning with the Grand Prix Attack." He won the Finnish Chess Championship five times, in 1970, 1971, 1978, 1981, and 1982. He became an International Master (IM) in 1975 and subsequently earned the title of Grandmaster (GM) in 1981.
Yrjö is known for having played competitive games against many famous chess players. At different times, he has achieved victories over Grandmasters Mark Taimanov, Jan Timman, and former World Chess Champions Anatoly Karpov and Mikhail Tal. Some of these victories are considered to be some of the best games in his career.
In the Chess Olympiad, he represented Finland twelve times between 1972 and 1998, with his best results being 11th-place finishes in 1974 (in the individual ranking) and 1982 (in the team ranking).