Winning blow: knight to d8 (c6·3)
c9-19647naming 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 1870 ShuffleRating — for advanced tacticians.
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 e3, rook a8, bishop h1, knight c6, pawn c2 d2 h2 b3 g3 f4.
Black: king c7, queen d8, rook b7, knight d4, pawn g5 h5 f7.
11 white and 7 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
White are ahead by 6 points of material (26 against 20; 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 c7.
It is White to move on move 25, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 3. Files fully open (no pawns of either colour): a, e — natural highways for the rooks and queen.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. Nxd8 Ne2+ 26. Qxe2 Kb6 27. Qe5
Why it works
- Best move. knight to d8 is exactly what the engine plays (#4).
- Spot on — queen to e2 (#3).
- A natural move: queen to e5.
- You win a piece — the queen.
- If instead Nxb3+, then cxb3 and you win the queen.
Move by move
- 25. Nxd8 — knight to d8 (capture)
Types in this puzzle
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
About this position
These pieces come from starting position #851.
SP-851 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on b1 and e1, the queen on g1.
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 99.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 80 of 100 — class A — most balanced. Engine evaluation of the starting position: +17 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #851Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-851
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