Attack on the uncastled king: knight to b5 (c3·23)
c9-27810naming 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.
An opening trap from this Chess960 starting position.
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 1750 ShuffleRating — for advanced tacticians.
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.
Early Chess960 traps punish natural but careless development. Look for a forcing move that exploits a piece the opponent has just placed on a poor square — a fork, a pin or a threat that wins material before either side is fully developed.
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 d1, queen g1, rook b1 e1, bishop a1 f1, knight h1 c3, pawn c2 d2 g2 h2 f3 b4 e4.
Black: king c8, queen a3, rook b8 e8, bishop a8 f8, knight f7 d8, pawn e5 f5 a7 b7 c7 d7 g7 h7.
15 white and 16 black pieces are on the board; the puzzle position arises after move 6.
The position in numbers
Black are ahead by 1 points of material (38 against 39; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on c8.
It is White to move on move 6, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 8. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: a.
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
6. Nb5 Qa2 7. Nxa7+ Qxa7 8. Qxa7
Why it works
- Great move! knight to b5 keeps the pressure (+5.2).
- Well found: knight to a7 (+5.2).
- Strong! queen to a7 is the sharp choice (+5.2).
- You win a piece — the queen.
- If instead Qa2, then Nxa7+ and you stay on top.
Move by move
- 6. Nb5 — knight to b5
- Qa2 — queen to a2
- 7. Nxa7+ — knight to a7 (capture) with check
- Qxa7 — queen to a7 (capture)
- 8. Qxa7 — queen to a7 (capture)
Types in this puzzle
King in the center
The king starts in the middle — and the storm reaches it first.
King in the center: in Chess960 the monarch may start on the d- or e-file, right in the line of fire, and the attack can reach him before he ever castles. The signs: the enemy king still sits on its central starting square while the files toward it are opening. Play to rip the center open — a pawn sacrifice usually pays off here. And if it is your king in the middle, castle at the very first opportunity.
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.
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 #834.
SP-834 · 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 b1 and e1, the queen on g1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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 BastionScout family; read right to left it becomes position 119.
The engine's main line opens with f4.
Morozov Balance Index: 89 of 100 — class A — most balanced. Engine evaluation of the starting position: +14 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #834Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-834
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads