Attack on the uncastled king: bishop to b5 (c4·3)
c9-24228naming 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 e1, queen h5, rook d1 h1, bishop c4 h4, knight c1, pawn b2 g2 h2 c3 d4 e4.
Black: king e8, rook f7 d8, bishop b8, knight b6, pawn c5 d5 e5 a7 b7.
13 white and 10 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
White are ahead by 13 points of material (34 against 21; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e1, the black king on e8.
It is White to move on move 23, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: a.
White hold the bishop pair, an edge in open lines. 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
23. Bb5+ Nd7 24. Rf1 c4 25. Qxf7#
Why it works
- Best move. bishop to b5 is exactly what the engine plays (#2).
- rook to f1 develops smoothly.
- Precise: queen to f7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Nd7, then Rf1 and you stay on top.
Move by move
- 23. Bb5+ — bishop to b5 with check
- Nd7 — knight to d7
- 24. Rf1 — rook to f1
- c4 — pawn to c4
- 25. Qxf7# — queen to f7 (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 #76.
SP-76 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on e1, the rooks on d1 and h1, the queen on f1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 892.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #76Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-76
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