You have a 4×5 chess board as follows:

You can move the four bishops in any order (not necessarily alternating black and white), provided that no move puts a piece in danger of being captured by a bishop of the opposite color.

What is the fewest number of moves needed for the black and white bishops to exchange places?

(In reply to Solution1 by Ariel)

The problem allows successive moves by the same color.  Black and white need not alternate.

Posted by Charlie on 2004-02-29 10:14:44