Winning blow: queen to a3 (a2·3)
c9-17127naming 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 b1, queen a2, rook a1 d1, bishop e3, knight f1 g3, pawn c2 d2 h2 b3 e4 f7.
Black: king c8, queen c6, rook b8, bishop b4, knight a3 f4, pawn a5 d5 e6 f6 c7 h7.
13 white and 12 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 5 points of material (34 against 29; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on c8.
It is White to move on move 21, with 3 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): g — natural highways for the rooks and queen. Half-open for White: a.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Qxa3 Bxa3 22. Rxa3
Why it works
- Great move! queen to a3 keeps the pressure (+3.9).
- Spot on — rook to a3 (+3.9).
- You reach a winning position (+3.9).
- If instead Bxa3, then Rxa3 and you stay on top.
Move by move
- 21. Qxa3 — queen to a3 (capture)
- Bxa3 — bishop to a3 (capture)
- 22. Rxa3 — rook to a3 (capture)
Types in this puzzle
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
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.
Defensive exchange
Trade off the attacker — the storm dies with it.
The defensive exchange: your opponent's attack runs on one specific piece — trade it off, and the storm dies down. Find the "engine" of the attack, the piece without which the mating threats stop working: usually the queen or an invading knight. Offer the trade even at a small cost — your king breathes, and the material comes back later. The mistake is greedily dodging the exchange and getting mated a pawn up.
About this position
These pieces come from starting position #877.
SP-877 · BastionScout — A c- or f-file king with at least one knight out on the edge.
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.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the BastionScout family; read right to left it becomes position 88.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #877Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-877
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