Tigran Vartanovich Petrosian (Armenian: Տիգրան Վարդանի Պետրոսյան, Russian: Тигран Вартанович Петросян; 17 June 1929 – 13 August 1984) was a Soviet-Armenian chess grandmaster and World Chess Champion from 1963 to 1969. He was nicknamed "Iron Tigran" due to his almost-impenetrable defensive playing style, which emphasized safety above all else. Petrosian is often credited with popularizing chess in Armenia.