Winning blow: knight to c7 (b5·8)
c9-22757naming 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 1290 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 b1, queen c3, rook c1, bishop g1, knight b3 b5, pawn b2 e2 d3 g3 h3 a4.
Black: king c8, queen a6, rook e7 e8, bishop d5, knight e5, pawn a5 f5 g5 h5 b7 c7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 26.
The position in numbers
Black are ahead by 2 points of material (29 against 31; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on c8.
It is White to move on move 26, with 40 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c, f.
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
26. Nxc7 Qc6 27. Nxd5 Qxc3 28. Rxc3+
Why it works
- Great move! knight to c7 keeps the pressure (+5.0).
- Spot on — knight to d5 (+5.0).
- Precise: rook to c3 is the top choice (+5.3).
- You win a piece — the queen.
- If instead Qc6, then Nxd5 and you win the bishop.
Move by move
- 26. Nxc7 — knight to c7 (capture)
- Qc6 — queen to c6
- 27. Nxd5 — knight to d5 (capture)
- Qxc3 — queen to c3 (capture)
- 28. Rxc3+ — rook to c3 (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.
Knight fork
One knight move attacks two targets at once — the opponent can only save one.
A fork is one move that attacks two targets at once, and no piece forks better than the knight. Look through the knight's eyes: it jumps in an L and never moves along straight lines, which is exactly why its threats get missed. Both victims of a knight fork always stand on squares of one color, while the knight strikes from the opposite color. Hunt for the square from which the knight hits the king and a heavy piece at once.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #687.
SP-687 · 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 f1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 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 464.
The engine's main line opens with f4.
Morozov Balance Index: 21 of 100 — class D — largest edge. Engine evaluation of the starting position: +36 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #687Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-687
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