Winning blow: rook to f8 (f5·2)
c9-12868naming 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 1280 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 h2, queen e1, rook f1 f5, bishop b1 g3, knight c1 d2, pawn a2 b2 g2 e6.
Black: king h8, queen g7, rook f8 g8, bishop a7 e8, knight a4 c8, pawn d3 c4 a5 b5 h5 h7.
12 white and 14 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
Black are ahead by 2 points of material (35 against 37; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on h2, the black king on h8.
It is White to move on move 25, with 45 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 6. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: c, d, h.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
25. Rxf8 Bd4 26. Rxg8+ Kxg8 27. Nf3
Why it works
- Great move! rook to f8 keeps the pressure (+4.2).
- Spot on — rook to g8 (+4.4).
- A natural move: knight to f3.
- You win a piece — the rook.
- If instead Bd4, then Rxg8+ and you win the rook.
Move by move
- 25. Rxf8 — rook to f8 (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.
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.
Rook fork
The rook attacks two targets along rank and file at the same time.
A rook fork attacks two targets from one square — one along the file, the other along the rank. Look for enemy pieces standing at a right angle to each other, both visible from a single safe square. This is bread and butter in endgames, where a rook check picks up loose pieces and pawns along the way. Test every rook check you have: does it also hit something valuable on the other line?
About this position
These pieces come from starting position #40.
SP-40 · RampartScout — A knight in the corner and the king out on the wing (b/g); like every family, it is closed under mirror twins.
The king starts on g1, the rooks on f1 and h1, the queen on d1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the RampartScout family; read right to left it becomes position 925.
The engine's main line opens with c4.
Morozov Balance Index: 26 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +34 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #40Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-40
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