Winning blow: queen to a6 (a4·3)
c9-26613naming 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 1200 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 a4, rook b1 f1, bishop d4, knight f3 c6, pawn e2 f2 h2 d3 g3 c4 a7.
Black: king c8, queen d7, rook a8 g8, bishop h8, knight d8 e8, pawn b4 f5 g5 d6 e6 h7.
14 white and 13 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
White are ahead by 1 points of material (35 against 34; 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 c8.
It is White to move on move 17, with 52 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: b.
The White king has 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
17. Qa6+ Qb7 18. Ne7+ Kd7 19. Qxb7+ Nxb7 20. Nxg8
Why it works
- Great move! queen to a6 keeps the pressure (+5.4).
- Spot on — knight to e7 (+5.5).
- Strong! queen to b7 is the sharp choice (+5.8).
- Best move. knight to g8 is exactly what the engine plays (+5.8).
- You win a piece — the queen.
- If instead Qb7, then Ne7+ and you stay on top.
Move by move
- 17. Qa6+ — queen to a6 with check
- Qb7 — queen to b7
- 18. Ne7+ — knight to e7 with check
- Kd7 — king to d7
- 19. Qxb7+ — queen to b7 (capture) with check
- Nxb7 — knight to b7 (capture)
- 20. Nxg8 — knight to g8 (capture)
Types in this puzzle
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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
About this position
These pieces come from starting position #803.
SP-803 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on b1 and f1, the queen on d1.
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.
The second rank carries 2 pawns with no defender at all: a2, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 147.
The engine's main line opens with g3.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #803Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-803
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