Attack on the uncastled king: rook to f8 (f1·21)
c9-24348naming 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.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1560 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.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
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 a1, rook b1 f1, bishop c5, knight e1 g3, pawn a2 g2 h2 b3 d3 e3 c4.
Black: king c8, queen a8, rook b8 f8, bishop g5 g8, knight d6 g6, pawn e4 b5 a7 c7 g7 h7.
14 white and 14 black pieces are on the board; the puzzle position arises after move 12.
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 c1, the black king on c8.
It is White to move on move 12, with 42 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen.
Black hold the bishop pair, an edge in open lines. The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
12. Rxf8+ Nxf8 13. Qxg7 O-O-O 14. Qxg5
Why it works
- Brilliant! The rook on f8 is a sacrifice that works — you stand better (+2.0).
- Well found: queen to g7 (+2.0).
- Precise: queen to g5 is the top choice (+2.2).
- You win a piece — the rook.
- If instead Nxf8, then Qxg7 and you stay on top.
Move by move
- 12. Rxf8+ — rook to f8 (capture) with check
- Nxf8 — knight to f8 (capture)
- 13. Qxg7 — queen to g7 (capture)
- O-O-O — king to b8
- 14. Qxg5 — queen to g5 (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.
Decoy
A sacrifice lures the king or a piece onto a fatal square.
A decoy is the mirror image of deflection: you sacrifice to drag the king or a piece onto a fatal square. The classic is a queen or rook sac whose capture pulls the king into a knight fork, a discovered check or mate. Find the square where the target will be hit, then find the offer it cannot refuse. Calculate to the very end — a decoy only works when the follow-up is forced.
About this position
These pieces come from starting position #781.
SP-781 · BastionScout — A c- or f-file king with at least one knight out on the edge.
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.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
The pawn on d2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionScout family; read right to left it becomes position 184.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #781Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-781
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