Rainer Knaak is a German chess Grandmaster born in 1953 in Güstrow, Germany. He earned his International Master title in 1974 and his Grandmaster title in 1975. Knaak won the East Germany Chess Championship around nine times from 1973 to 1985. He also competed in the Chess Olympiads on eight occasions from 1974 to 1990.
Knaak transitioned into chess journalism in the 1990s and has been an editor of the chess magazine Schach. He has been a part of ChessBase, a chess software company, and contributed to the development of its programs. In collaboration with Karsten Müller, Knaak worked on the "Complete Ruy Lopez" DVD production, with the aim of making the Ruy Lopez opening more accessible to budding chess players.
Knaak also worked in chess education, running training group projects for young players in the German Chess Federation (DSB) and offering private lessons too. Several of his trainees, such as Elisabeth Pähtz and Arik Braun, have achieved the Grandmaster title themselves.