Winning blow: queen to b8 (c7·3)
c9-15682naming 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 4: a forced checkmate in four moves — every reply is covered.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 2250 ShuffleRating — expert level — few solve it at first try.
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.
A mate in four is a longer forced net: each of your moves is a check or an irresistible threat, and the king is driven step by step to a square where it is finally trapped. Verify that the defender has exactly one reply at every branch.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
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 b1, queen c7, rook a1 g1, bishop g2, knight h1, pawn b2 c2 h2 a3 g4.
Black: king a6, rook b8, knight h6, pawn a4 b5 d6 h7.
11 white and 7 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 18 points of material (30 against 12; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on a6.
It is White to move on move 24, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): e, f — natural highways for the rooks and queen. Half-open for White: d.
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
24. Qxb8 d5 25. Bxd5 Nf5 26. Qb7+ Ka5 27. Qa7#
Why it works
- Best move. queen to b8 is exactly what the engine plays (#3).
- Spot on — bishop to d5 (#2).
- Precise: queen to b7 is the top choice (#1).
- Best move. queen to a7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead d5, then Bxd5 and you win the rook.
Move by move
- 24. Qxb8 — queen to b8 (capture)
- d5 — pawn to d5
- 25. Bxd5 — bishop to d5 (capture)
- Nf5 — knight to f5
- 26. Qb7+ — queen to b7 with check
- Ka5 — king to a5
- 27. Qa7# — queen to a7 and it is checkmate
Types in this puzzle
Mate in 4+
A long forced mating combination.
Mate in four or longer is a marathon of forcing moves where the grip must never loosen. The tools are the same: checks, double threats and sacrifices that deny the opponent a single free tempo. Do not juggle the whole tree at once — walk the main line all the way to mate first, then verify the side branches. If somewhere the defender finds one quiet move that holds, your very first move was wrong.
About this position
These pieces come from starting position #810.
SP-810 · RampartScout — King on the wing (b/g) with a knight on the rim (a/h) — the rarest family.
The king starts on b1, the rooks on a1 and g1, the queen on c1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartScout family; read right to left it becomes position 149.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 43 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +28 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #810Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-810
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