Winning blow: pawn to c5 (c4·9)
c9-24072naming 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 1390 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 a4, rook e5, knight e2, pawn b2 h2 c4 f4 d5.
Black: king c8, queen b6, rook d6, knight f8, pawn g4 a5 h5 e6 g6 c7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
Black are ahead by 1 points of material (22 against 23; 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 25, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: a, e, g.
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
25. c5 Qxc5 26. dxe6 Nxe6 27. Qe8+ Kb7 28. Rxc5
Why it works
- Great move! pawn to c5 keeps the pressure (+5.2).
- Well found: pawn to e6 (+5.6).
- Precise: queen to e8 is the top choice (+5.8).
- Great move! rook to c5 keeps the pressure (+5.9).
- You win a piece — the queen.
- If instead Qxc5, then dxe6 and you stay on top.
Move by move
- 25. c5 — pawn to c5
- Qxc5 — queen to c5 (capture)
- 26. dxe6 — pawn to e6 (capture)
- Nxe6 — knight to e6 (capture)
- 27. Qe8+ — queen to e8 with check
- Kb7 — king to b7
- 28. Rxc5 — rook to c5 (capture)
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.
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.
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #655.
SP-655 · 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 e1.
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.
The pawn on b2, c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 208.
The engine's main line opens with f4.
Morozov Balance Index: 51 of 100 — class B — balanced. Engine evaluation of the starting position: +26 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #655Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-655
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