Attack on the uncastled king: pawn to e6 (d5·37)
c9-06643naming 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 1060 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 f1, queen b1, rook a1 h1, bishop c2, knight d3 e5, pawn a2 b2 e2 g2 c3 f3 h4 d5.
Black: king f8, queen c8, rook a8 h8, bishop g1 e6, knight d6 e8, pawn a5 f5 c6 b7 d7 e7 g7 h7.
15 white and 16 black pieces are on the board; the puzzle position arises after move 10.
The position in numbers
Black are ahead by 3 points of material (36 against 39; 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 10, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 8. No file is fully open, so the heavy pieces have to be pried in.
Black 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
10. dxe6 Be3 11. exd7 Qc7 12. dxe8=R+
Why it works
- Great move! pawn to e6 keeps the pressure (+3.9).
- Spot on — pawn to d7 (+4.0).
- Precise: pawn to e8 is the top choice (+4.0).
- You win a piece — the bishop.
- If instead Be3, then exd7 and you win the bishop.
Move by move
- 10. dxe6 — pawn to e6 (capture)
- Be3 — bishop to e3
- 11. exd7 — pawn to d7 (capture)
- Qc7 — queen to c7
- 12. dxe8=R+ — pawn to e8 (capture) with check
Types in this puzzle
King in the center
The king starts in the middle — and the storm reaches it first.
King in the center: in Chess960 the monarch may start on the d- or e-file, right in the line of fire, and the attack can reach him before he ever castles. The signs: the enemy king still sits on its central starting square while the files toward it are opening. Play to rip the center open — a pawn sacrifice usually pays off here. And if it is your king in the middle, castle at the very first opportunity.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
About this position
These pieces come from starting position #413.
SP-413 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on f1, the rooks on a1 and h1, the queen on b1.
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 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: d2.
The setup belongs to the BastionGuard family; read right to left it becomes position 744.
The engine's main line opens with c3.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #413Provenance
Mined from the project's engine self-play games.
Verified by Stockfish at depth 20+.
Solution forcedness confirmed (verified).
Pack 006 · SP-413
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