Chess is a very tough game, and psychologically a tough game. And of course chess needs a lot of qualities, human qualities. And so you must have very strong nervous system and then you must be well prepared, you must be able to work a lot.
Anatoly KarpovMy studies with Botvinnik brought me immense benefit, particularly the homework assignments which forced me to refer to chess books and to work independently.
Anatoly Karpov