Attack on the uncastled king: bishop to h3 (f1·5)
c9-22734naming 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 d1, rook h1 a4, bishop f1, knight e1, pawn b2 d2 h2 b3 g3 e4.
Black: king c8, rook b8 f8, bishop d8, knight e8, pawn e5 b6 d6 b7 g7 h7.
11 white and 11 black pieces are on the board; the puzzle position arises after move 15.
The position in numbers
Material is level — 22 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on d1, the black king on c8.
It is White to move on move 15, with 31 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): a, c, f — natural highways for the rooks and queen.
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
15. Bh3+ Rf5 16. Bxf5+ Kc7 17. Rc4#
Why it works
- Great move! bishop to h3 keeps the pressure (#2).
- Well found: bishop to f5 (#1).
- Strong! rook to c4 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Rf5, then Bxf5+ and you win the rook.
Move by move
- 15. Bh3+ — bishop to h3 with check
- Rf5 — rook to f5
- 16. Bxf5+ — bishop to f5 (capture) with check
- Kc7 — king to c7
- 17. Rc4# — rook to c4 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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
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 #269.
SP-269 · BastionScout — King shifted to c or f, with a knight committed to the corner from move one.
The king starts on c1, the rooks on b1 and h1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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: a2.
The setup belongs to the BastionScout family; read right to left it becomes position 600.
The engine's main line opens with a4.
Morozov Balance Index: 98 of 100 — class A — most balanced. Engine evaluation of the starting position: 0 centipawns for White (depth 48, 400 000 000 nodes).
In 50 self-play games White scored 48.0% (95% CI 34.8–61.5%).
Explore position #269Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-269
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