Attack on the uncastled king: rook to d7 (d1·7)
c9-27929naming 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, rook d1 h1, bishop a1 f1, knight c4, pawn a2 f2 g2 e3 c5 h5.
Black: king g8, queen d7, rook e8 h8, bishop e5, knight f7, pawn f5 b6 h6 a7 c7 g7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
Black are ahead by 6 points of material (25 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 21, with 34 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 — natural highways for the rooks and queen. Half-open for White: b.
White 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
21. Rxd7 Bxa1 22. Rxc7 O-O 23. cxb6 axb6 24. Nxb6
Why it works
- Great move! rook to d7 keeps the pressure (+3.6).
- Spot on — rook to c7 (+3.7).
- Precise: pawn to b6 is the top choice (+3.5).
- Best move. knight to b6 is exactly what the engine plays (+3.8).
- You win a piece — the queen.
- If instead Bxa1, then Rxc7 and you win the queen.
Move by move
- 21. Rxd7 — rook to d7 (capture)
- Bxa1 — bishop to a1 (capture)
- 22. Rxc7 — rook to c7 (capture)
- O-O — king to h8
- 23. cxb6 — pawn to b6 (capture)
- axb6 — pawn to b6 (capture)
- 24. Nxb6 — knight to b6 (capture)
Types in this puzzle
Remove the defender
Capture the guard first — then take what it protected.
Removing the defender is the straightforward plan: capture the guard first, then take what it guarded. Unlike deflection, the defender is not lured away — it is traded off or destroyed on the spot. Stare at the target you crave and ask who defends it, and whether that defender can be profitably eaten. Count the whole capture sequence, not just the first move — the trade must pay off at the end.
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.
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 #18.
SP-18 · RampartGuard — King on the wing (b/g) with both knights on inner files.
The king starts on g1, the rooks on e1 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.
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: a2.
The setup belongs to the RampartGuard family; read right to left it becomes position 935.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 3 of 100 — class D — largest edge. Engine evaluation of the starting position: +52 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #18Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-18
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