Attack on the uncastled king: rook to h8 (h1·9)
c9-22495naming 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 3: a forced sequence that ends in checkmate.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1630 ShuffleRating — for advanced tacticians.
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.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
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 c1, queen e1, rook a1 h1, knight c3, pawn a2 c2 d2 b3 g3.
Black: king d8, queen g5, rook a4 b8, knight d6, pawn b6 f6 a7 c7 d7.
10 white and 10 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
Material is level — 27 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 d8.
It is White to move on move 18, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): e, h — natural highways for the rooks and queen. Half-open for White: f.
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
18. Rh8+ Qg8 19. Rxg8+ Ne8 20. Qxe8#
Why it works
- Great move! rook to h8 keeps the pressure (#2).
- Well found: rook to g8 (#1).
- Precise: queen to e8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Qg8, then Rxg8+ and you win the queen.
Move by move
- 18. Rh8+ — rook to h8 with check
- Qg8 — queen to g8
- 19. Rxg8+ — rook to g8 (capture) with check
- Ne8 — knight to e8
- 20. Qxe8# — queen to e8 (capture) 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 3
A forced checkmate in three moves.
Mate in three is a forced staircase: each of your moves narrows the opponent's choices, and the third one ends the game. Look for the start among checks and sacrifices — quiet first moves are rare in mating problems, but deliciously sneaky. Keep the tree in your head: every defense gets its own branch. Do not stop calculating after move two — see the final mating picture with your own eyes.
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 #627.
SP-627 · ThroneGuard — Both knights start on inner files (b–g) while the king sits centrally on d or e — one of 204 positions filed here.
The king starts on d1, the rooks on b1 and f1, the queen on e1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
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: h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 227.
The engine's main line opens with b3.
Morozov Balance Index: 75 of 100 — class B — balanced. Engine evaluation of the starting position: +19 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #627Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-627
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