Attack on the uncastled king: bishop to d5 (c4·6)
c9-20531naming 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 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.
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 a2, queen h6, rook e1 e7, bishop a3 c4, knight c3, pawn d2 f2 h2 b3 a4.
Black: king b8, queen c6, rook a8 d8, bishop f5 h8, knight d4, pawn b4 e5 d6 b7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 27.
The position in numbers
White are ahead by 1 points of material (33 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 a2, the black king on b8.
It is White to move on move 27, with 60 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): c, g — natural highways for the rooks and queen. Half-open for White: e.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
27. Bd5 Qb6 28. Rxb7+ Qxb7 29. Bxb7
Why it works
- Great move! bishop to d5 keeps the pressure (+3.0).
- Well found: rook to b7 (+3.8).
- Strong! bishop to b7 is the sharp choice (+3.5).
- You win a piece — the queen.
- If instead Qb6, then Rxb7+ and you stay on top.
Move by move
- 27. Bd5 — bishop to d5
- Qb6 — queen to b6
- 28. Rxb7+ — rook to b7 (capture) with check
- Qxb7 — queen to b7 (capture)
- 29. Bxb7 — bishop to b7 (capture)
Types in this puzzle
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
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.
Winning exchange
A forced series of captures on one square ends in your favour.
A winning exchange is a forced series of captures on one square that leaves you ahead in material. It is pure arithmetic: count the attackers and defenders of the square and note the value of every piece in the queue. Capture in the right order — cheap pieces first, expensive ones later — or a winning trade turns into a losing one. The classic error is stopping the count halfway and missing the opponent's final recapture.
About this position
These pieces come from starting position #839.
SP-839 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on b1, the rooks on a1 and e1, the queen on f1.
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.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartGuard family; read right to left it becomes position 114.
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 48, 400 000 000 nodes).
Explore position #839Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-839
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads