Winning blow: queen to a5 (a2)
c9-16501naming 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 1150 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 a2, rook b1 e1, bishop e3 d5, knight c4, pawn d2 e2 h2 c3 g3.
Black: king d7, queen b5, rook b8 e8, bishop d6, knight a5 f8, pawn b3 f6 g6 h7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 1 points of material (33 against 32; 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 d7.
It is White to move on move 21, with 48 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): a — natural highways for the rooks and queen. Half-open for White: b, f.
White 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
21. Qxa5 Qxa5 22. Nxa5
Why it works
- Great move! queen to a5 keeps the pressure (+5.6).
- Well found: knight to a5 (+5.7).
- You win a piece — the queen.
- If instead Qxa5, then Nxa5 and you win the queen.
Move by move
- 21. Qxa5 — queen to a5 (capture)
- Qxa5 — queen to a5 (capture)
- 22. Nxa5 — knight to a5 (capture)
Types in this puzzle
Winning exchange
A forced series of captures on one square ends in your favour.
A winning exchange is a forced series of captures on one square that leaves you ahead in material. It is pure arithmetic: count the attackers and defenders of the square and note the value of every piece in the queue. Capture in the right order — cheap pieces first, expensive ones later — or a winning trade turns into a losing one. The classic error is stopping the count halfway and missing the opponent's final recapture.
About this position
These pieces come from starting position #783.
SP-783 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and e1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on c2 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 176.
The engine's main line opens with b4.
Morozov Balance Index: 6 of 100 — class D — largest edge. Engine evaluation of the starting position: +48 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #783Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-783
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