Mate in 3: rook to d6 (d1·4)
c9-09229naming 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 1860 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 b2, queen f6, rook d1, bishop a6, knight b5, pawn a2 c2 b3 e3 f5 h5.
Black: king d7, queen f8, rook h8, bishop h1, pawn g5 b6 d6 h6 a7 f7.
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 3 points of material (26 against 23; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on d7.
It is White to move on move 25, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: d, g.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. Rxd6+ Qxd6 26. Qxd6+ Ke8 27. Nc7#
Why it works
- Best move. rook to d6 is exactly what the engine plays (#2).
- Spot on — queen to d6 (#1).
- Precise: knight to c7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Qxd6, then Qxd6+ and you win the queen.
Move by move
- 25. Rxd6+ — rook to d6 (capture) with check
- Qxd6 — queen to d6 (capture)
- 26. Qxd6+ — queen to d6 (capture) with check
- Ke8 — king to e8
- 27. Nc7# — knight to c7 and it is checkmate
Types in this puzzle
Knight mate
The knight lands the killing blow from its unique angle.
In a knight mate the final blow comes from the knight — the only piece whose check can never be blocked. That makes it lethal against a cramped king: only a king move or capturing the knight itself can help. The sign: the squares around the king are occupied or covered, and there is a hop from which the knight checks while staying untouchable. Bring the knight over early — it is slower than the long-range pieces, but its strike cannot be parried.
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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #738.
SP-738 · BastionGuard — King off-centre on c or f with both knights on inner files.
The king starts on c1, the rooks on b1 and h1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 407.
The engine's main line opens with b3.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #738Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-738
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