Attack on the uncastled king: rook to b4 (b1·6)
c9-16703naming 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 920 ShuffleRating — for beginners taking their first steps in Chess960 tactics.
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 h1, bishop a1 f1, knight d1, pawn c2 g2 h2 e3 f3.
Black: king g8, queen c8, rook b4 h8, bishop c6 g7, knight c5, pawn a4 a7 c7 d7 f7 h7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 11.
The position in numbers
Black are ahead by 1 points of material (33 against 34; 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 11, with 29 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): b — natural highways for the rooks and queen. Half-open for White: a, d.
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
11. Rxb4 Bxa1 12. Qxa1
Why it works
- Great move! rook to b4 keeps the pressure (+4.5).
- Spot on — queen to a1 (+4.7).
- You win a piece — the rook.
- If instead Bxa1, then Qxa1 and you win the rook.
Move by move
- 11. Rxb4 — rook to b4 (capture)
- Bxa1 — bishop to a1 (capture)
- 12. Qxa1 — queen to a1 (capture)
Types in this puzzle
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
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 #402.
SP-402 · RampartGuard — King on the wing (b/g) with both knights on inner files.
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.
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 743.
The engine's main line opens with c4.
Morozov Balance Index: 96 of 100 — class A — most balanced. Engine evaluation of the starting position: +8 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #402Provenance
Mined from the project's engine self-play games.
Pack 004 · SP-402
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads