Two reasonably competent chess players are discussing chess in a bar. A duffer comes up and challenges them to simultaneous matches, with the duffer playing white on one game, and black on the other. He offers a substantial bet on the outcome. However, since he's inexperienced, he will win the bet unless the two experienced players as a whole do better than the duffer. (That is, two draws or one win and one loss will result in the duffer winning the bet.)

The challenge is accepted, and play starts. After a few moves, the experienced players throw up their hands in disgust, and pay off the bet.

Question 1: What happened?

Question 2: Having accepted the challenge, what ought the experienced players to have done in order to win?

(In reply to adjourn by Cheradenine)

My favorite answer is that the experts set up chess clocks before starting.

Since the duffer is copying moves, his time in his white game will strictly exceed the expert's white time, and his black time will exceed the expert's black time.

With careful planning, the experts can ensure that the duffer either loses both games on time, or realizes that he's in trouble and quits waiting for moves to copy.

For example, assume that the clocks are set to the standard 2:30 per side for 40 moves. The clocks are started for both whites. The expert white waits 2:29, then moves, and punches his clock. The duffer copies the move, the punches the other clock. The black expert waits 2:29, then makes a move and punches his clock.

Thereafter, both experts play as rapidly as possible. Since it will take the duffer a non-zero amount of time to copy moves, his clock will drop first, in both games.

Posted by Jim Lyon on 2002-09-12 14:18:07