Winning blow: knight to c6 (d4·5)
c9-16268naming 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.
A fork made possible by the Chess960 piece placement.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1010 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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 a2, queen d3, rook e1, bishop d1, knight g3 d4, pawn c2 d2 g2 h2 f4.
Black: king d8, queen a5, rook h8, bishop a4, knight f6 f8, pawn c6 a7 g7 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 1 points of material (28 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 a2, the black king on d8.
It is White to move on move 21, with 50 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): b, e — natural highways for the rooks and queen. Half-open for White: a.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Nxc6+ Kc8 22. Nxa5 Ne6 23. Rxe6
Why it works
- Great move! knight to c6 keeps the pressure (+10.8).
- Spot on — knight to a5 (+11.3).
- Precise: rook to e6 is the top choice (+13.6).
- You win a piece — the queen.
- If instead Kc7, then Nxa5 and you win the queen.
Move by move
- 21. Nxc6+ — knight to c6 (capture) with check
Types in this puzzle
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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 #705.
SP-705 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and h1, the queen on e1.
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.
The second rank carries 2 pawns with no defender at all: a2, g2.
The setup belongs to the BastionGuard family; read right to left it becomes position 443.
The engine's main line opens with f4.
Morozov Balance Index: 24 of 100 — class D — largest edge. Engine evaluation of the starting position: +35 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #705Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-705
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