Revisiting the retractor December 28, 2007
Click "Stop" on your browser to stop the music and "Refresh" to start it.

A few years ago we published a proposal by Bobby Fischer to modify the rules of chess. The former world champion, our report said, was tired of the "unbearable preponderance of tactics in chess" and had submitted a rule modification to FIDE that allowed players to take back moves and play something else instead. Naturally the article, which was published on April 1st, was a joke.

So the retractor was not introduced into current-day chess, and the "touch-move" rule is still strictly enforced. However there is an area of the game in which you can – in fact must – take back moves and execute an alternative line instead. Here's a simple example:

B. Sommer, Deutsches Wochenschach 1910

White takes back his last move and mates in one

To clarify: in the above position White has just executed a move. He takes back this move and plays instead a different move, one that immediately mates the black king. Try to solve it yourself. The answer is given at the bottom of this page.

Today's problem is similar, and starts with an even simpler position:

Dr. J. Sunyer, Chess Amateur 1923

White and Black retract their last moves,
then Black plays a move that allows White to mate in one.

Just so there are no misunderstandings: in the above position first White takes back his last move, then Black takes back the move he made immediately before that move. Now Black plays a different move, and that allows White to mate him immediately. Apologies to readers who have seen this famous problem before.

Solution to the problem by B. Sommer: White takes back the move 1.exf6 e.p. (Black previous move was ...f7-f5) and instead plays 1.e8Q mate.