Winning blow: queen to a4 (a5)
c9-13761naming 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 1010 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 f1, queen a5, rook g1 b3, bishop d1 e1, knight e2 f3, pawn f2 h2 g3.
Black: king g8, queen b7, rook c8 f8, bishop a4 c7, knight b6 e7, pawn f5 d6 g7 h7.
11 white and 12 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
Black are ahead by 1 points of material (34 against 35; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on g8.
It is White to move on move 20, with 41 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 4. Files fully open (no pawns of either colour): a, b, c, e — natural highways for the rooks and queen. Half-open for White: d.
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
20. Qxa4 Ra8 21. Qc4+ Kh8 22. Qc2
Why it works
- Great move! queen to a4 keeps the pressure (+3.6).
- Spot on — queen to c4 (+3.9).
- A natural move: queen to c2.
- You win a piece — the bishop.
- If instead Ng6, then Qa1 and you win the bishop.
Move by move
- 20. Qxa4 — queen to a4 (capture)
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
About this position
These pieces come from starting position #200.
SP-200 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on f1, the rooks on d1 and h1, the queen on a1.
The queenside rook already stands on d1, so castling long moves only the king, from f1 to c1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
The pawn on g2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 669.
The engine's main line opens with c4.
Morozov Balance Index: 13 of 100 — class D — largest edge. Engine evaluation of the starting position: +41 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #200Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-200
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