A challenging problem with an elegant solution — and a few well-disguised near-solutions.
Nice to Meet: Grimshaw
In chess composition, a Grimshaw is a classic theme where two Black pieces – most often a rook (♜) and a bishop (♝) – mutually interfere with each other on the same square.
When either piece moves onto that critical square, it blocks the other piece’s line of defense. The beauty comes when White’s mating responses depend on which Black piece made the self-block.
This elegant idea often creates two distinct checkmates, one for each blocking piece – a hallmark of artistic problem design.
Once you’ve seen a Grimshaw in action, it’s hard not to smile at how Black’s own pieces get in each other’s way – and that’s exactly what makes this theme so beloved among chess composers.
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The composer managed to arrange, on the very same board, two pairs of Black pieces (♜ & ♝), each pair defending its own sector, unaware of the other.
First, White plays the winning key move, preparing a direct threat: ♖b5#.
After that, the Black pieces try to save the ♚ by blocking White’s pieces:
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➡️On the left side: the pair attempts to place a block on b4, cutting off the ♖ from reaching b5.
➡️On the right side: the pair tries a more subtle defense by blocking the ♗ on g4, which seals off e6 from the ♚.
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The side effects of these White-piece blockades are self-blocks by the Black pieces:
Left side:
🔀 ♜b4 blocks the ♝, allowing the ♘ to reach c3#;
♝b4 blocks the ♜, allowing the ♙ to capture on c4#.
Right side:
🔀 a ♝ blocking the ♜ allows the ♕ to reach e5#;
if the ♜ blocks the ♝, the ♕ captures on e4#. (Think about why it’s specifically the ♕.)
That’s the Grimshaw idea, but the sophisticated and precise content of this puzzle doesn’t end there.
We’ve seen that when a ♜ blocks the ♝’s defense of the ♙ on e4, the ♕ delivers mate by capturing there.
But what happens if the ♝ isn’t blocked by the ♜, and instead stops defending e4 by capturing the ♘ on e8 and guarding the dangerous square b5 from there?
This time it’s not the ♕ who captures on e4, but rather the ♙ (Think about why.)
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We suggest — and highly recommend — paying attention in this puzzle to the near-solutions as well; they are truly beautiful:
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Why not bring the ♖ to b5 already on the very first move? There is just one Black defense preventing it from being the key move.
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And what about White trying to start with ♗d6? Or the move ♗xc8? Did you check those?
🎯We especially liked:
There are two Black defensive-tries that abandon the defense of the ♟ on e4 — either ♜f5 or ♝xe8.
In each case, the ♕ is left solely responsible for covering a different square (e6 or d6).
This mechanism means that capturing the ♟ and delivering mate must always be done in exactly the right way — and only that way.