Winning blow: knight to a5 (c4·3)
c9-27974naming 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 d2, queen d4, bishop h1 e3, knight c4, pawn b2 h2 c3 f4 d5.
Black: king c8, queen a5, rook a8, bishop h6 f7, knight d8, pawn b3 f5 d6 c7 h7.
10 white and 11 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 (23 against 28; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d2, the black king on c8.
It is White to move on move 24, with 26 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): a, e, g — natural highways for the rooks and queen.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Nxa5 Rxa5 25. Bf3 Bg6 26. Qb4 Ra1 27. Qxb3
Why it works
- Great move! knight to a5 keeps the pressure (+4.2).
- bishop to f3 develops smoothly.
- Precise: queen to b4 is the top choice (+3.7).
- Best move. queen to b3 is exactly what the engine plays (+4.2).
- You win a piece — the queen.
- If instead Rxa5, then Bf3 and you win the queen.
Move by move
- 24. Nxa5 — knight to a5 (capture)
- Rxa5 — rook to a5 (capture)
- 25. Bf3 — bishop to f3
- Bg6 — bishop to g6
- 26. Qb4 — queen to b4
- Ra1 — rook to a1
- 27. Qxb3 — queen to b3 (capture)
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
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 #799.
SP-799 · 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 e1, the queen on b1.
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.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 160.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 7 of 100 — class D — largest edge. Engine evaluation of the starting position: +47 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #799Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-799
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