Attack on the uncastled king: bishop to g7 (c3·2)
c9-19380naming 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 c1, rook a1 d1, bishop c3, knight e3 f3, pawn a2 b2 f2 g2 h2 c4.
Black: king c8, rook a8 h8, bishop f4 e8, knight g8, pawn c5 e6 a7 b7 g7 h7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
Material is level — 25 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on c1, the black king on c8.
It is White to move on move 13, with 38 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: e.
Black hold the bishop pair, an edge in open lines. The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
13. Bxg7 Nh6 14. Bxh8
Why it works
- Great move! bishop to g7 keeps the pressure (+5.1).
- Well found: bishop to h8 (+5.4).
- You win a piece — the rook.
- If instead Nh6, then Bxh8 and you win the rook.
Move by move
- 13. Bxg7 — bishop to g7 (capture)
- Nh6 — knight to h6
- 14. Bxh8 — bishop to h8 (capture)
Types in this puzzle
X-ray
A long-range piece acts through an enemy piece on the same line.
An X-ray lets a long-range piece act through an enemy piece standing on the same line — its power shines straight through. The square behind looks safe or defended, and that illusion is exactly what the tactic exploits. Check your rooks, bishops and queens: is a key square or a target hiding behind an enemy piece on their line? When counting captures on a square, include the X-ray attackers — they join the fight the moment the line opens.
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.
Development punish
Half the army still asleep — the attack breaks through.
Punishing lazy development: half of your opponent's army is asleep on its starting squares, which means you outnumber him where the fight is. Count not the pieces on the board but the pieces in play — if five or more of his pieces have never moved, look for a forcing attack. The sign is a development lead plus open lines toward his king. Strike immediately: give him two quiet moves and the advantage evaporates.
About this position
These pieces come from starting position #712.
SP-712 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
The king starts on c1, the rooks on a1 and h1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the BastionGuard family; read right to left it becomes position 445.
The engine's main line opens with c4.
Morozov Balance Index: 37 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +30 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #712Provenance
Mined from the project's engine self-play games.
Pack 005 · SP-712
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