The twice chess world champion Tigran Petrosyan, was given the nickname "Iron Tigran" by the contemporaries for its unrivaled art of protection. It was due to Tigran Petrosyan that chess became popular in Armenia and became one of the most favorite sports among Armenians. Nowadays chess is included in the number of the compulsory subjects in the schools of Armenia. Alongside with various achievements Tigran Petrosyan is multiple champion of Armenia and the USSR, International Grandmaster, winner of numerous international competitions, ninefold winner of the Chess Olympiad in the USSR team. In 1962, he defeated Mikhail Botvinnik in a world championship match and won the title of the ninth world chess champion, and in 1966 defended the title of champion by winning Boris Spassky in the world championship match.