Attack on the uncastled king: rook to d8 (d4·5)
c9-21802naming 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 in 2: the first move creates an unstoppable threat, the second delivers mate.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1450 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.
Mate in two usually opens with a forcing move — a check, a capture or an unstoppable threat — that strips the king of squares or defenders, so the follow-up mate becomes unavoidable. Look for the first move that leaves the opponent only losing replies.
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 a3, queen d1, rook f1 d4, bishop e1, pawn f2 b3 a4 g4 h4.
Black: king c8, rook f7 a8, bishop g6, pawn c4 a5 e6 b7 g7 h7.
10 white and 10 black pieces are on the board; the puzzle position arises after move 27.
The position in numbers
White are ahead by 8 points of material (27 against 19; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a3, the black king on c8.
It is White to move on move 27, with 31 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 — natural highways for the rooks and queen. Half-open for White: c, e.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
27. Rd8+ Kc7 28. Qd6#
Why it works
- Great move! rook to d8 keeps the pressure (#1).
- Spot on — queen to d6 (#).
- The line ends in a forced mate in 2.
- If instead Kc7, then Qd6# and it is mate.
Move by move
- 27. Rd8+ — rook to d8 with check
- Kc7 — king to c7
- 28. Qd6# — queen to d6 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
Mate in 2
A forced checkmate in two moves.
Mate in two: your move, any reply, then the mating blow. Start with the most forcing first moves — checks and sacrifices that shrink the opponent's options to almost nothing. Against every single reply you must have a mate ready, so check them all without exception. The common failure is analyzing the pretty defense and forgetting the boring one.
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 #538.
SP-538 · 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 e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 517.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 61 of 100 — class B — balanced. Engine evaluation of the starting position: +23 centipawns for White (depth 49, 400 000 000 nodes).
Explore position #538Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-538
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