Attack on the uncastled king: bishop to d4 (c3·4)
c9-14843naming 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 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.
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, queen c1, rook b1 f1, bishop c3 d7, knight g4 c6, pawn a2 b2 c2 h2 f3 e4.
Black: king g8, queen h3, rook b8 h8, bishop b6, knight f8, pawn g3 d5 e5 a7 f7 g7.
14 white and 12 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
White are ahead by 6 points of material (37 against 31; 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 17, with 7 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 6 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: d, g.
White hold the bishop pair, an edge in open lines. 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
17. Bd4 Nxd7 18. Bxb6 Nf6 19. Qd2
Why it works
- Great move! bishop to d4 keeps the pressure (+3.1).
- Spot on — bishop to b6 (+3.3).
- A natural move: queen to d2.
- You reach a winning position (+3.3).
- If instead Bxd4+, then Nxd4 and you stay on top.
Move by move
- 17. Bd4 — bishop to d4
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.
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.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
About this position
These pieces come from starting position #137.
SP-137 · RampartScout — King on b or g with a knight already on the edge — the least common of the position families (72 in all).
The king starts on g1, the rooks on b1 and h1, the queen on c1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the RampartScout family; read right to left it becomes position 825.
The engine's main line opens with b4.
Morozov Balance Index: 55 of 100 — class B — balanced. Engine evaluation of the starting position: +25 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #137Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-137
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