Attack on the uncastled king: knight to f6 (d7)
c9-23404naming 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 1760 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 g2, queen b2, rook f1 h3, bishop f3 d4, knight c3 d7, pawn a3 c4 h6.
Black: king g8, queen c8, rook d3 h8, knight e5, pawn f4 g5 a7 b7 f7 h7.
11 white and 11 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 6 points of material (34 against 28; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g2, the black king on g8.
It is White to move on move 24, with 61 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 6. Files fully open (no pawns of either colour): d, e — natural highways for the rooks and queen. Half-open for White: b, f, g.
White hold the bishop pair, an edge in open lines. 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
24. Nf6+ Kf8 25. Qb4+ Qc5 26. Qxc5#
Why it works
- Great move! knight to f6 keeps the pressure (#2).
- Well found: queen to b4 (#1).
- Precise: queen to c5 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Kf8, then Qb4+ and you stay on top.
Move by move
- 24. Nf6+ — knight to f6 with check
- Kf8 — king to f8
- 25. Qb4+ — queen to b4 with check
- Qc5 — queen to c5
- 26. Qxc5# — queen to c5 (capture) and it is checkmate
Types in this puzzle
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.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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 #9.
SP-9 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
The king starts on g1, the rooks on f1 and h1, the queen on a1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on g2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 953.
The engine's main line opens with h4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #9Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-9
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