How many hours a day do grandmasters spend on the game?

Some truly hard-working GMs, such as Bobby Fischer or Gata Kamsky, could spend an entire day at the board, going over opening ideas, replaying the games of their potential rivals or refining their endgame technique.

Other GMs often go days at a time without having any contact with chess. Only when preparing for a tournament or match do they crack the books.

Viktor Korchnoi, a two-time challenger for the world championship, once came up with a formula.

“A chessplayer must work as many hours a day as a tournament game normally runs,” he said. In that way, he becomes accustomed to the a daily rhythm of chess thinking. When a typical, clocked game lasted five hours, Korchnoi would spend five hours studying.

Now that time controls have been shortened and a tournament game typically ends an hour or so earlier, Korchnoi says four hours a day is enough.

But the former Russian said it is much easier to study nowadays because “computers have interfered in chess life.”

“Before, to play to a new opening I had to gather material for two weeks and study it for a month,” he said.

“Now it takes a half hour.”