There's a couple of score keepers, recording the moves and keeping track of the time with a stop-watch. Typical time limits in qualifying rounds are 5 or 6 hours each for the game, in title matches 9 or 10 hours with the play over two days. If a player uses less than a minute it's counted as "no time" and nothing is deducted from their allotment, so when a player has used all his time he carrys on playing within a minute per move.