Winning blow: queen to a3 (c1·2)
c9-20397naming 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 1280 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 h1, queen c1, rook f1 c5, pawn a2 h2 d3 b4 h4 e5.
Black: king a8, rook c8 g8, bishop h3, pawn a3 d4 b5 h5 g7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 38.
The position in numbers
White are ahead by 7 points of material (25 against 18; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on h1, the black king on a8.
It is White to move on move 38, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): c, f — natural highways for the rooks and queen. Half-open for White: g.
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
38. Qxa3+ Kb8 39. Rxb5+ Kc7 40. Qa7+
Why it works
- Best move. queen to a3 is exactly what the engine plays (#4).
- Spot on — rook to b5 (#3).
- Precise: queen to a7 is the top choice (#2).
- You win decisive material (+15.0).
- If instead Kb8, then Rxb5+ and you stay on top.
Move by move
- 38. Qxa3+ — queen to a3 (capture) with check
Types in this puzzle
Hanging piece
A piece is left without protection — just take it.
A hanging piece is simply an unprotected piece you can take for free. It sounds primitive, yet most amateur games are decided exactly this way. Build the habit: before every move, sweep the board and note every undefended piece, yours and theirs. The classic mistake is hunting for a brilliant combination when all you need to do is bend down and pick up the gift.
About this position
These pieces come from starting position #686.
SP-686 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on c1, the rooks on b1 and h1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
The pawn on d2 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 468.
The engine's main line opens with a4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #686Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-686
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