Winning blow: queen to a6 (a7·3)
c9-21447naming 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 a7, rook h3, bishop c3, pawn c2 d2 f4 g4 c6.
Black: king c8, queen d8, rook b8 e8, bishop f8, pawn a3 b3 e6 f7 g7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
Black are ahead by 5 points of material (22 against 27; 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 24, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): h — natural highways for the rooks and queen. Half-open for White: a, b, e.
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
24. Qa6+ Kc7 25. Ba5+ Kd6 26. c7+ Ke7 27. cxd8=Q+
Why it works
- Great move! queen to a6 keeps the pressure (+6.4).
- Well found: bishop to a5 (+6.8).
- Precise: pawn to c7 is the top choice (+7.0).
- Best move. pawn to d8 is exactly what the engine plays (+7.3).
- You win a piece — the queen.
- If instead Kc7, then Ba5+ and you stay on top.
Move by move
- 24. Qa6+ — queen to a6 with check
- Kc7 — king to c7
- 25. Ba5+ — bishop to a5 with check
- Kd6 — king to d6
- 26. c7+ — pawn to c7 with check
- Ke7 — king to e7
- 27. cxd8=Q+ — pawn to d8 (capture) with check
Types in this puzzle
Pawn fork
A humble pawn steps forward and attacks two pieces at once.
A pawn fork is a single pawn step that attacks two pieces at once. Since the pawn is the cheapest unit on the board, the trade is always a bargain — the opponent saves only one of the two targets. The pattern: two enemy pieces on the same rank, one file apart, with a square for your pawn between them. Before parking your pieces near enemy pawns, always ask whether one little push forks them both.
Discovered check
The moving piece opens a check — and is free to grab anything meanwhile.
With a discovered check the moving piece unmasks a check from the piece standing behind it. While the king deals with the check, the piece that moved grabs whatever it likes, free of charge. Look for your long-range piece on a line with the enemy king, with exactly one of your own pieces in between. The rule: among all the ways to step aside, pick the one that captures or attacks the most expensive loot.
Promotion
The pawn reaches the last rank and becomes a queen — decisively.
Promotion turns a pawn on the last rank into a queen and rewrites the evaluation on the spot. In tactics the passer rarely walks in for free — usually a sacrifice clears its path. Count the tempi: how many moves does the pawn need, and can the defender stop it in time? And watch the promotion square itself — it must be out of enemy reach or won by force in your combination.
About this position
These pieces come from starting position #850.
SP-850 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
The king starts on c1, the rooks on b1 and e1, the queen on h1.
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.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the BastionGuard family; read right to left it becomes position 103.
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 43, 400 000 000 nodes).
Explore position #850Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-850
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