Mate in 3: bishop to d5 (a2·2)
c9-28420naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Mate in 3: a forced sequence that ends in checkmate.
Difficulty 1630 ShuffleRating — for advanced tacticians.
White to move — find the best continuation
How to recognize this tactic
In Chess960 the pieces start on unfamiliar squares, so tactics appear earlier and from unusual angles. Do not trust classical patterns — read the actual lines of the bishops, the rooks and the queen from where they really stand in this position.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
General method: before you move, list the forcing candidates — every check, every capture, every direct threat — and calculate those first. The solution to a tactic is almost always among them.
Position on the board
White: king c1, queen e8, rook d1 a3, bishop a2, knight d3, pawn b2 c2 f3 h4 a5.
Black: king b7, rook g2 a8, pawn d4 f4 b5 h5 a6 d6 c7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 13 points of material (30 against 17; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on b7.
It is White to move on move 25, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 7. Files fully open (no pawns of either colour): e, g — natural highways for the rooks and queen. Half-open for White: d.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. Bd5+ c6 26. Qxc6+ Kb8 27. Qb7#
Why it works
- Great move! bishop to d5 keeps the pressure (#2).
- Spot on — queen to c6 (#1).
- Precise: queen to b7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead c6, then Qxc6+ and you stay on top.
Move by move
- 25. Bd5+ — bishop to d5 with check
- c6 — pawn to c6
- 26. Qxc6+ — queen to c6 (capture) with check
- Kb8 — king to b8
- 27. Qb7# — queen to b7 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
Mate in 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #840.
SP-840 · BastionScout — King off-centre on c or f with a knight starting on the rim (a/h).
The king starts on c1, the rooks on a1 and f1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: e2.
The setup belongs to the BastionScout family; read right to left it becomes position 125.
The engine's main line opens with f4.
Morozov Balance Index: 75 of 100 — class B — balanced. Engine evaluation of the starting position: +19 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #840Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-840
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