Attack on the uncastled king: pawn to c5 (d4·57)
c9-17083naming 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.
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 1060 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.
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 e1, rook a1 e2, bishop g1 a4, pawn a2 b2 h2 c3 g3 d4.
Black: king c8, queen e8, rook a8 f8, bishop c7, knight c5 d6, pawn c4 g5 c6 d7 h7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 2 points of material (31 against 33; 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 17, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): e, f — natural highways for the rooks and queen.
White 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
17. dxc5 Qf7 18. cxd6 Rxa4 19. dxc7
Why it works
- Great move! pawn to c5 keeps the pressure (+3.3).
- Spot on — pawn to d6 (+3.4).
- Precise: pawn to c7 is the top choice (+4.3).
- You win a piece — the bishop.
- If instead Qf7, then cxd6 and you win the knight.
Move by move
- 17. dxc5 — pawn to c5 (capture)
- Qf7 — queen to f7
- 18. cxd6 — pawn to d6 (capture)
- Rxa4 — rook to a4 (capture)
- 19. dxc7 — pawn to c7 (capture)
Types in this puzzle
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.
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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #828.
SP-828 · BastionScout — King off-centre on c or f with a knight starting on the rim (a/h).
The king starts on c1, the rooks on a1 and f1, the queen on e1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the BastionScout family; read right to left it becomes position 140.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 13 of 100 — class D — largest edge. Engine evaluation of the starting position: +41 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #828Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-828
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