Attack on the uncastled king: bishop to d5 (a8)
c9-12938naming 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 2170 ShuffleRating — expert level — few solve it at first try.
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 f1, queen d7, rook a1 h1, bishop c1 a8, knight e1, pawn a2 c2 h2 a3 d3 g4.
Black: king f8, rook h8, bishop b6, knight d4, pawn f4 f6 g7 h7.
13 white and 8 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
White are ahead by 19 points of material (34 against 15; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on f8.
It is White to move on move 17, with 41 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): b, e — natural highways for the rooks and queen. Half-open for White: f.
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
17. Bd5 Ne6 18. Bxe6 Bd4 19. Qf7#
Why it works
- Sensible development: bishop to d5.
- Spot on — bishop to e6 (#1).
- Precise: queen to f7 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Ne6, then Bxe6 and you win the knight.
Move by move
- 17. Bd5 — bishop to d5
- Ne6 — knight to e6
- 18. Bxe6 — bishop to e6 (capture)
- Bd4 — bishop to d4
- 19. Qf7# — queen to f7 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 #453.
SP-453 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on f1, the rooks on a1 and h1, the queen on g1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on c1 and d1; their long diagonals reach h6 and h5 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 698.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #453Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-453
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