Nikolai Krogius
Nikolai Vladimirovich Krogius (July 22, 1930 – July 14, 2022) was a Russian Chess Grandmaster, International Arbiter (1985), psychologist, chess coach, chess administrator, and author. He coached World Champion Boris Spassky for many years. He also was chairman of the USSR Chess Federation. He was the co-winner of the 1993 World Senior Chess Championship.