Attack on the uncastled king: bishop to a6 (e2·7)
sf-u-0074naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Mate in 3: a forced sequence that ends in checkmate.
Chess960 twist: use the unusual starting setup of the pieces.
Difficulty 1630 ShuffleRating — for advanced tacticians.
White to move — find the best continuation
How to recognize this tactic
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.
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.
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.
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 b2, queen d4, rook b1, bishop e2, knight g3, pawn a2 c2 d2 h2 b3 d6.
Black: king c8, rook b8, bishop a8, knight h6, pawn b6 c6 e6 a7 d7 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
White are ahead by 9 points of material (26 against 17; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on c8.
It is White to move on move 18, with 52 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): f, g — natural highways for the rooks and queen. Half-open for White: e.
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
18. Ba6+ Rb7 19. Qh8+ Ng8 20. Qxg8#
Why it works
- Great move! bishop to a6 keeps the pressure (#2).
- Spot on — queen to h8 (#1).
- Precise: queen to g8 is the top choice (#).
- The line ends in a forced mate in 3.
- If instead Rb7, then Qh8+ and you stay on top.
Move by move
- 18. Ba6+ — bishop to a6 with check
- Rb7 — rook to b7
- 19. Qh8+ — queen to h8 with check
- Ng8 — knight to g8
- 20. Qxg8# — queen to g8 (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.
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.
Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 013
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads