Attack on the uncastled king: pawn to d7 (c6·3)
c9-06215naming 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 920 ShuffleRating — for beginners taking their first steps in Chess960 tactics.
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 g1, rook e1 h1, bishop f1, knight c1 d1, pawn d2 f2 g2 h4 c6.
Black: king g8, rook e8 h8, bishop a8 b8, knight c8, pawn h5 a6 e6 d7 f7 g7.
11 white and 12 black pieces are on the board; the puzzle position arises after move 12.
The position in numbers
Black are ahead by 1 points of material (24 against 25; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on g8.
It is White to move on move 12, with 27 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen. Half-open for White: a, e.
Black hold the bishop pair, an edge in open lines. The White king has 0 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
12. cxd7 Rf8 13. dxc8=N
Why it works
- Great move! pawn to d7 keeps the pressure (+3.2).
- Spot on — pawn to c8 (+3.1).
- You win a piece — the knight.
- If instead Rf8, then dxc8=N and you win the knight.
Move by move
- 12. cxd7 — pawn to d7 (capture)
- Rf8 — rook to f8
- 13. dxc8=N — pawn to c8 (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.
Underpromotion
Promoting to a knight or rook — not a queen — is the only way to win.
Underpromotion means choosing a knight, rook or bishop instead of a queen — and winning precisely because of it. The usual hero is the knight, which delivers a check or a fork from the promotion square in a way no queen can. A rook is chosen when a fresh queen would produce stalemate. When your pawn reaches the last rank, never promote on autopilot — first ask what the knight can do.
About this position
These pieces come from starting position #2.
SP-2 · RampartGuard — A b- or g-file king and two knights on inner files (b–g).
The king starts on g1, the rooks on e1 and h1, the queen on b1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the RampartGuard family; read right to left it becomes position 951.
The engine's main line opens with h4.
Morozov Balance Index: 61 of 100 — class B — balanced. Engine evaluation of the starting position: +23 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #2Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 004 · SP-2
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