Reshevsky was a tough and forceful player who was superb at positional play, but could also play brilliant tactical chess when warranted. He often used huge amounts of time in the opening, a dangerous tactic which sometimes forced him to play the rest of the game in a very short amount of time. That sometimes unsettled Reshevsky's opponents, but at other times resulted in blunders on his part. Reshevsky's inadequate study of the opening and his related tendency to fall into time pressure may have been the reasons that, despite his great talent, he never became world champion; he himself acknowledged this in his book on chess upsets. This Reshevsky shortcoming was similarly noted by GM Larry Evans in commentary contained in Fischer's book "My 60 Memorable Games".