Winning blow: pawn to b5 (a4·10)
c9-23750naming 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 g1, rook a1 d1, bishop h1, knight c2, pawn b2 e2 h2 c3 a4 g4 f5.
Black: king c8, queen g8, rook d7 d8, bishop b5, knight b8 f8, pawn a5 d5 g5 b7 c7 f7 h7.
13 white and 14 black pieces are on the board; the puzzle position arises after move 15.
The position in numbers
Black are ahead by 3 points of material (32 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 c1, the black king on c8.
It is White to move on move 15, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: d.
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
15. axb5 Rd6 16. Rxa5 Nfd7 17. Rxd5 Rxd5 18. Bxd5
Why it works
- Great move! pawn to b5 keeps the pressure (+2.8).
- Spot on — rook to a5 (+2.7).
- Precise: rook to d5 is the top choice (+3.3).
- Great move! bishop to d5 keeps the pressure (+3.1).
- You win a piece — the rook.
- If instead Rd6, then Rxa5 and you win the bishop.
Move by move
- 15. axb5 — pawn to b5 (capture)
- Rd6 — rook to d6
- 16. Rxa5 — rook to a5 (capture)
- Nfd7 — knight to d7
- 17. Rxd5 — rook to d5 (capture)
- Rxd5 — rook to d5 (capture)
- 18. Bxd5 — bishop to d5 (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.
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 #667.
SP-667 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
The king starts on c1, the rooks on a1 and d1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 193.
The engine's main line opens with f4.
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 #667Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-667
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