Mate in 3: rook to b7 (b1·7)
c9-19430naming 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 1980 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 d1, queen b8, rook b1 e1, knight e2, pawn c2 g2 h2 d3 a5 e5.
Black: king d7, queen a3, rook a6 h8, pawn d4 g4 f5 e6 h6.
11 white and 9 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 4 points of material (28 against 24; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on d7.
It is White to move on move 24, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen. Half-open for White: f.
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
24. Rb7+ Kc6 25. Qc7+ Kd5 26. Nf4#
Why it works
- Great move! rook to b7 keeps the pressure (#2).
- Spot on — queen to c7 (#1).
- Precise: knight to f4 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kc6, then Qc7+ and you stay on top.
Move by move
- 24. Rb7+ — rook to b7 with check
- Kc6 — king to c6
- 25. Qc7+ — queen to c7 with check
- Kd5 — king to d5
- 26. Nf4# — knight to f4 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.
About this position
These pieces come from starting position #522.
SP-522 · ThroneGuard — King on a central file (d/e) with both knights on inner files — the classic-type setup.
The king starts on d1, the rooks on a1 and h1, the queen on c1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneGuard family; read right to left it becomes position 533.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 11 of 100 — class D — largest edge. Engine evaluation of the starting position: +42 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #522Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-522
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