Genna (Gennadi Borisovich) Sosonko was born in Troitsk in Siberia, but spent all his life in Leningrad, where he also achieved a university degree in economic geography.
Genna became national master in the Soviet Union, and during 1966-1971 he was the trainer of Mikhail Tal and later on Viktor Korchnoi.
Genna immigrated from the USSR in 1972 and settled in the Netherlands. He became an international master in 1974 and a grandmaster in 1976. Sosonko played for the Netherlands from 1974; in eleven Olympiads he had the superb overall score of +28 -4 = 64. In the 1990s and 2000s, he was the Dutch team captain. Genna Sosonko is a two-time Dutch Champion (1973 and 1978), a two-time winner of the tournament at Wijk aan Zee (1978 and 1981), winner of tournaments in Barcelona and Lugano in 1976, and Polanicazdroj in 1993 and prize-winner in Tilburg, New York, Bad Lauterberg, Sao Paulo, London, Indonesia and Reykjavik.
From 1975 to 1982 he was one of the top twenty players in the world, achieving his highest rating of 2595 at the start of 1981. He has made a significant contribution to opening theory, especially to his favourite Catalan and Sicilian Dragon.
In 2004 he stopped competing to focus on journalism and literature. He is the author of wonderful memoirs which were published in several languages. In recent years he has often worked as a commentator on tournaments featuring the world's leading grandmasters, describing their battles in English, Dutch and Russian.