Career
After a brief foray into "over-the-board" play, he turned to correspondence chess in the early 1960s with immediate success (joint first place in the Union of the Soviet Socialist Republics Correspondence Championship in 1962) He became an International Correspondence Chess Grandmaster in 1966, and would go on to compete in the final of the World Correspondence Championship five times. Foreign over-the-board play, he was awarded the International Master title in 1975. Estrin wrote several chess books and was an authority on the Two Knights Defense.
His game with Hans Berliner in which Berliner played the Two Knights Defense and defeated Estrin is one of the most famous and important games in correspondence chess.