Attack on the uncastled king: queen to c8 (a8·3)
c9-12803naming 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.
Mate: a forcing sequence that ends the game — the king has no escape.
Mate in 4: a forced checkmate in four moves — every reply is covered.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 2250 ShuffleRating — expert level — few solve it at first try.
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.
This is a forced mating attack. Start from the enemy king: which of its squares are already covered, and which move takes away the rest while keeping the king in check? Forcing moves — checks and captures — are what turn an attack into mate.
A mate in four is a longer forced net: each of your moves is a check or an irresistible threat, and the king is driven step by step to a square where it is finally trapped. Verify that the defender has exactly one reply at every branch.
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.
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 a8, rook a1 f1, bishop b1 e3, knight e1, pawn a2 b2 c3 g3 h4.
Black: king g8, rook h8, bishop c8, knight e4, pawn c5 b6 h6 a7 f7 g7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
White are ahead by 16 points of material (33 against 17; 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 16, with 38 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): d, e — natural highways for the rooks and queen. Half-open for White: f.
White 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
16. Qxc8+ Kh7 17. Qf5+ Kg8 18. Qxf7+ Kh7 19. Bxe4#
Why it works
- Great move! queen to c8 keeps the pressure (#3).
- Spot on — queen to f5 (#2).
- Precise: queen to f7 is the top choice (#1).
- Best move. bishop to e4 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kh7, then Qf5+ and you win the bishop.
Move by move
- 16. Qxc8+ — queen to c8 (capture) with check
- Kh7 — king to h7
- 17. Qf5+ — queen to f5 with check
- Kg8 — king to g8
- 18. Qxf7+ — queen to f7 (capture) with check
- Kh7 — king to h7
- 19. Bxe4# — bishop to e4 (capture) and it is checkmate
Types in this puzzle
Boden's mate
Two bishops cross their diagonals over a king blocked by its own pieces.
Boden's mate crosses two bishop diagonals over a king blocked by its own pieces. The classic victim has castled on the queenside: its own rook and pawns have stolen the escape squares, and the bishops slash crosswise. The trigger is usually a queen sacrifice that blasts open the second diagonal. Whenever the enemy king is boxed in by its friends, ask whether both of your bishops can reach it on crossing diagonals.
Mate in 4+
A long forced mating combination.
Mate in four or longer is a marathon of forcing moves where the grip must never loosen. The tools are the same: checks, double threats and sacrifices that deny the opponent a single free tempo. Do not juggle the whole tree at once — walk the main line all the way to mate first, then verify the side branches. If somewhere the defender finds one quiet move that holds, your very first move was wrong.
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 #404.
SP-404 · RampartGuard — A b- or g-file king and two knights on inner files (b–g).
The king starts on g1, the rooks on a1 and h1, the queen on d1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
The pawn on f2 is defended by the king alone — the classic soft spot of the standard setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 750.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 83 of 100 — class A — most balanced. Engine evaluation of the starting position: +16 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #404Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-404
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