Mate in 3: queen to b8 (c8)
c9-24077naming 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.
A fork made possible by the Chess960 piece placement.
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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 c2, queen c8, rook a1 e1, knight e5, pawn a2 h2 c3 f3 g3 e4.
Black: king b6, bishop a3 g8, knight c4, pawn b5 f5 g5 h6 c7.
11 white and 9 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
White are ahead by 14 points of material (28 against 14; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c2, the black king on b6.
It is White to move on move 23, 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): d — natural highways for the rooks and queen. Half-open for White: b.
Black hold the bishop pair, an edge in open lines. The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
23. Qb8+ Ka6 24. Qa8+ Kb6 25. Nd7#
Why it works
- Best move. queen to b8 is exactly what the engine plays (#2).
- Spot on — queen to a8 (#1).
- Precise: knight to d7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ka6, then Qa8+ and you stay on top.
Move by move
- 23. Qb8+ — queen to b8 with check
- Ka6 — king to a6
- 24. Qa8+ — queen to a8 with check
- Kb6 — king to b6
- 25. Nd7# — knight to d7 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.
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
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 #830.
SP-830 · RampartScout — The king starts on b or g while a knight begins on the a- or h-file — the smallest family.
The king starts on b1, the rooks on a1 and e1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartScout family; read right to left it becomes position 132.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #830Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-830
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