The Chess Variant Pages

Founded 1990

The magazine to broaden your chess horizons

Volume 5, Issue 36 ISSN 0958-8248 Autumn 2000

Problem 322 Solution

322: this is Grid Chess - another unplayable variant, as it's very hard to achieve anything at all, particularly mate. Only moves crossing one or more of the grid lines are legal - and this applies also to checks - apparent king-captures that don't cross grid-lines do not give check. In this diagram the K could legally stand on d1 or c2. On the other hand, he can never legally reach any of the corners.

This is a seriesmover, where Black makes 7 successive legal moves (with White not moving at all) in such a way that White can then deliver checkmate. There are two ways to do this. Each sequence of moves will be unique - for problemists, it spoils it completely if Black's moves can be swapped about a bit. Again, this has one dagger for difficulty.


Grid chess
Series helpmate in 7, 2 solutions

322: Solution. Only move of bK is to capture the wR - which certainly doesn't assist White to give mate. So bB must shield wR to let bK move. Only possible mates are along an edge: wR can't move to d1 (as this move doesn't cross a grid line) and after 2 introductory B moves to block d3 (for Kd4) it would take another 5 moves to reach the top. So White mating moves will be Ra2 or Rh2. Most elegantly, the two solutions do in fact mate on each of the two edges, and are completely distinct. 1.Bf3 2.Be2 3.Kf2 4.Kf3 5.Kg4 6.Kh5 7.Bg4 Rh2 - no interposition, Bh3 doesn't cross a line! 1.Be4 2.Bd3 3.Kd4 4.Kc5 5.Kb5 6.Ka4 7.Bb5 Ra2 The K-paths cannot be varied. Two completely determined and distinct solutions from such a simple setup was quite a find.