Attack on the uncastled king: pawn to d5 (d4·3)
c9-25482naming 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 1250 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 h1, queen d2, rook b1 f1, bishop c3, knight c2 e3, pawn a2 b2 e2 f2 h2 g3 c4 d4.
Black: king d8, queen c6, rook b8 g8, bishop h8, knight a4 e6, pawn c5 d6 g6 a7 b7 e7 f7 h7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 11.
The position in numbers
Material is level — 36 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on h1, the black king on d8.
It is White to move on move 11, with 5 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 8 pawns, Black 8. No file is fully open, so the heavy pieces have to be pried in.
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
11. d5 Bxc3 12. bxc3 Qa6 13. dxe6
Why it works
- Great move! pawn to d5 keeps the pressure (+4.3).
- Well found: pawn to c3 (+4.3).
- Strong! pawn to e6 is the sharp choice (+4.3).
- You win a piece — the bishop.
- If instead Bxc3, then bxc3 and you stay on top.
Move by move
- 11. d5 — pawn to d5
- Bxc3 — bishop to c3 (capture)
- 12. bxc3 — pawn to c3 (capture)
- Qa6 — queen to a6
- 13. dxe6 — pawn to e6 (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.
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.
Blocking save
Block the check with tempo — and turn the game around.
The blocking save: you interpose a piece against the check — not passively, but with tempo, so the blocker creates a threat of its own. Such a block turns defense into attack. Whenever you are checked, compare all three replies — capture, move the king, interpose — and among the interpositions hunt for the one that counterattacks. The mistake is automatically stepping aside with the king when an active block would have turned the game around.
About this position
These pieces come from starting position #235.
SP-235 · ThroneScout — A central king (d or e), but with a knight posted out on the a- or h-file.
The king starts on d1, the rooks on b1 and g1, the queen on c1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the ThroneScout family; read right to left it becomes position 625.
The engine's main line opens with c4.
Morozov Balance Index: 80 of 100 — class A — most balanced. Engine evaluation of the starting position: +17 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #235Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-235
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