Attack on the uncastled king: bishop to g6 (c2·3)
c9-27221naming 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 1420 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 e1, queen b1, rook a1 h1, bishop c2 h2, knight e2 e3, pawn a2 b2 f2 g2 h4.
Black: king e8, queen e5, rook a8 h8, bishop f7 d8, knight f4 g6, pawn a5 b5 h5 c6 d7 g7.
13 white and 14 black pieces are on the board; the puzzle position arises after move 15.
The position in numbers
Black are ahead by 1 points of material (36 against 37; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on e8.
It is White to move on move 15, with 37 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): e — natural highways for the rooks and queen. Half-open for White: c, d.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
15. Bxg6 Bxg6 16. Bxf4
Why it works
- Great move! bishop to g6 keeps the pressure (+2.9).
- Well found: bishop to f4 (+2.9).
- You win a piece — the knight.
- If instead Bxg6, then Bxf4 and you win the knight.
Move by move
- 15. Bxg6 — bishop to g6 (capture)
- Bxg6 — bishop to g6 (capture)
- 16. Bxf4 — bishop to f4 (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.
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.
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.
About this position
These pieces come from starting position #509.
SP-509 · ThroneGuard — King home on d or e, knights kept off the a- and h-files — the family of the standard starting array.
The king starts on e1, the rooks on a1 and h1, the queen on b1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 552.
The engine's main line opens with c3.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #509Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-509
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