Winning blow: queen to c7 (b8·4)
c9-19632naming 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.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1560 ShuffleRating — club-player level.
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.
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 c1, queen b8, bishop h2, knight e7 f8, pawn b2 c2 f2 h3 a4.
Black: king c5, rook a8, knight g3, pawn a5 g5 d6 h6 b7 c7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 29.
The position in numbers
White are ahead by 9 points of material (23 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 c1, the black king on c5.
It is White to move on move 29, with 30 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: d, g.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
29. Qxc7+ Kb4 30. Qc3+ Kxa4 31. Qb3#
Why it works
- Best move. queen to c7 is exactly what the engine plays (#2).
- Spot on — queen to c3 (#1).
- Precise: queen to b3 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kb4, then Qc3+ and you stay on top.
Move by move
- 29. Qxc7+ — queen to c7 (capture) with check
- Kb4 — king to b4
- 30. Qc3+ — queen to c3 with check
- Kxa4 — king to a4 (capture)
- 31. Qb3# — queen to b3 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
About this position
These pieces come from starting position #799.
SP-799 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
The king starts on c1, the rooks on a1 and e1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 160.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 7 of 100 — class D — largest edge. Engine evaluation of the starting position: +47 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #799Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-799
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