Attack on the uncastled king: rook to d8 (d1·23)
c9-25787naming 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 1200 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 b1, queen g1, rook a1 d1, bishop e1 b5, knight c1, pawn b2 c2 g2 h2 a3 e4.
Black: king b8, queen h8, rook a8 d8, bishop e8 f8, knight e7 c8, pawn a4 e6 g6 h6 b7 c7.
13 white and 14 black pieces are on the board; the puzzle position arises after move 12.
The position in numbers
Black are ahead by 3 points of material (34 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 b1, the black king on b8.
It is White to move on move 12, with 46 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): d, f — natural highways for the rooks and queen.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
12. Rxd8 Bxb5 13. Bc3 Qg8 14. Qc5 Qf7 15. Qxb5
Why it works
- Great move! rook to d8 keeps the pressure (+3.2).
- bishop to c3 develops smoothly.
- Precise: queen to c5 is the top choice (+3.0).
- Best move. queen to b5 is exactly what the engine plays (+2.9).
- You win a piece — the rook.
- If instead Bxb5, then Bc3 and you stay on top.
Move by move
- 12. Rxd8 — rook to d8 (capture)
- Bxb5 — bishop to b5 (capture)
- 13. Bc3 — bishop to c3
- Qg8 — queen to g8
- 14. Qc5 — queen to c5
- Qf7 — queen to f7
- 15. Qxb5 — queen to b5 (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.
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
About this position
These pieces come from starting position #858.
SP-858 · RampartGuard — King on the wing (b/g) with both knights on inner files.
The king starts on b1, the rooks on a1 and d1, the queen on h1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
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 RampartGuard family; read right to left it becomes position 101.
The engine's main line opens with e4, putting a pawn straight into the centre.
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 #858Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-858
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