Attack on the uncastled king: bishop to a6 (e2·6)
c9-27384naming 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.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1420 ShuffleRating — club-player level.
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.
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.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
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 c1, queen b6, rook d1 e1, bishop g1 e2, knight f1 h5, pawn b2 c2 h2 g3 a4 f4 e5.
Black: king c8, queen d5, rook a8 e8, bishop f8 g8, knight g6 e7, pawn a5 c6 f6 d7 g7 h7.
15 white and 14 black pieces are on the board; the puzzle position arises after move 15.
The position in numbers
White are ahead by 1 points of material (38 against 37; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on c8.
It is White to move on move 15, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: d.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
15. Ba6+ Rxa6 16. Qxa6+
Why it works
- Great move! bishop to a6 keeps the pressure (#5).
- Well found: queen to a6 (#4).
- You win decisive material (+15.0).
- If instead Rxa6, then Qxa6+ and you stay on top.
Move by move
- 15. Ba6+ — bishop to a6 with check
- Rxa6 — rook to a6 (capture)
- 16. Qxa6+ — queen to a6 (capture) with check
Types in this puzzle
Check chase
Every move is a check — the king is chased into losing ground.
In a check chase every one of your moves is a check, so the opponent never gets a free second. The king is herded across the board until it loses a piece or walks into a decisive blow. Such lines are the easiest to calculate: each check allows only a handful of replies, so try them all. Make it a habit to start calculating any sharp position with the checks — they are the most forcing moves on the board.
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 #893.
SP-893 · 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 a1 and e1, the queen on b1.
The king already stands on c1, so castling long moves only the rook, from a1 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: g2.
The setup belongs to the BastionScout family; read right to left it becomes position 72.
The engine's main line opens with a4.
Morozov Balance Index: 43 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +28 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #893Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-893
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