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 A switch solution - maybe not the optimal one... by slsl)

The numbering is wrong... "a3b2" should be "a2b3", and so on. Also, the two first moves can be switched, and so can the two last moves, so there are four solutions.

Posted by Federico Kereki on 2004-03-02 07:03:49