| Gennadi Sosonko | |
| Birthname: | Gennadi Borisovich Sosonko |
| Country: | Soviet Union (before 1972) Netherlands (after 1972) |
| Birth Date: | 1943 5, df=y |
| Birth Place: | Troitsk, Russian SFSR, Soviet Union |
| Grandmaster (1976) | |
| Peakranking: | No. 16 (January 1981) |
| Peakrating: | 2595 (January 1981) |
| Fideid: | 1000039 |
Gennadi "Genna" Borisovich Sosonko (Russian: Геннадий Борисович Сосонко, Gennady Borisovich Sosonko; born 18 May 1943) is a Russian-born Dutch chess grandmaster and writer. He has been awarded the title Grandmaster (GM) by FIDE and is a twice Dutch champion.
Born in Troitsk, Russia, Sosonko won the Leningrad juniors' championship in 1958.
He legally emigrated from the Soviet Union to the Netherlands via Israel in 1972. This move was instrumental in enabling him to focus on playing chess professionally and improving his chess results dramatically. He quickly earned IM and then the GM title.
Sosonko won the Dutch Championship in 1973 and 1978 (jointly).His tournament record includes 1st at Wijk aan Zee 1977, 1st at Nijmegen 1978, 3rd at Amsterdam 1980, 1st at Wijk aan Zee 1981, 3rd at Tilburg 1982 and 4th at Haninge 1988. He also drew a match with Jan Timman (+1 =0 −1) in 1984.
Sosonko played for the Dutch team at the Chess Olympiad eleven times, in 1974–84, and 1988–96. He won two individual medals: gold at Haifa 1976, bronze at Nice 1974, and two team medals: silver at Haifa 1976, and bronze at Thessaloniki 1988.
FIDE, the World Chess Federation, awarded Sosonko the International Master (IM) title in 1974, the GM title in 1976 and the FIDE Senior Trainer title in 2004.[1]
Sosonko has authored six non-technical chess books centering heavily on his chess life in the Soviet Union and his relationships with and memories of both leading Soviet players and lesser-known characters in chess history.