Attack on the uncastled king: bishop to c7 (g3·2)
c9-27376naming 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 1290 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 b1, queen f1, rook h1 a5, bishop g3 f7, knight g5, pawn b2 c2 g2 h2 a6.
Black: king b8, queen d4, rook a8 h8, bishop c6 f6, knight c8 g8, pawn d3 b6 a7 c7 g7 h7.
12 white and 14 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
Black are ahead by 4 points of material (33 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 b1, the black king on b8.
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 5 pawns, Black 6. Files fully open (no pawns of either colour): e, f — natural highways for the rooks and queen. Half-open for White: d.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
18. Bxc7+ Kxc7 19. Ne6+ Kd7 20. Nxd4
Why it works
- Great move! bishop to c7 keeps the pressure (+4.5).
- Well found: knight to e6 (+4.9).
- Strong! knight to d4 is the sharp choice (+5.3).
- You win a piece — the queen.
- If instead Kxc7, then Ne6+ and you stay on top.
Move by move
- 18. Bxc7+ — bishop to c7 (capture) with check
- Kxc7 — king to c7 (capture)
- 19. Ne6+ — knight to e6 with check
- Kd7 — king to d7
- 20. Nxd4 — knight to d4 (capture)
Types in this puzzle
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.
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.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
About this position
These pieces come from starting position #729.
SP-729 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
The king starts on b1, the rooks on a1 and h1, the queen on f1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 425.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 24 of 100 — class D — largest edge. Engine evaluation of the starting position: +35 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #729Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-729
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