Attack on the uncastled king: rook to e1 (c1·2)
c9-18851naming 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 b1, rook a1 c1, bishop g1 h1, pawn b2 f2 h2 g3 a4 d5 e5 b6.
Black: king b8, queen e1, rook a8 c8, knight d8 f8, pawn a5 b5 g5 f6 b7 d7 h7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 15.
The position in numbers
Black are ahead by 8 points of material (24 against 32; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on b8.
It is White to move on move 15, with 19 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 7. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen.
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
15. Rxe1 fxe5 16. Rxe5 Nf7 17. Re1 Ng6 18. axb5
Why it works
- Great move! rook to e1 keeps the pressure (+4.0).
- Spot on — rook to e5 (+4.0).
- Precise: rook to e1 is the top choice (+3.5).
- Best move. pawn to b5 is exactly what the engine plays (+3.1).
- You win a piece — the queen.
- If instead fxe5, then Rxe5 and you win the queen.
Move by move
- 15. Rxe1 — rook to e1 (capture)
- fxe5 — pawn to e5 (capture)
- 16. Rxe5 — rook to e5 (capture)
- Nf7 — knight to f7
- 17. Re1 — rook to e1
- Ng6 — knight to g6
- 18. axb5 — pawn to b5 (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 #943.
SP-943 · RampartGuard — The king starts out on a wing file, b or g, with neither knight in a corner.
The king starts on b1, the rooks on a1 and c1, the queen on e1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the RampartGuard family; read right to left it becomes position 16.
The engine's main line opens with a4.
Morozov Balance Index: 31 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +32 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #943Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-943
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