Attack on the uncastled king: bishop to f3 (h1·6)
c9-15031naming 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 1200 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 d1, queen a7, rook b1, bishop h1, knight a1 c1, pawn a2 d2 e2 h2 c3 g5 c6.
Black: king d8, queen g8, rook f3 b8, bishop e5 g6, knight a8, pawn g3 a4 b7 d7 e7 h7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 12.
The position in numbers
Black are ahead by 4 points of material (30 against 34; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on d8.
It is White to move on move 12, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 6. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: b.
Black hold the bishop pair, an edge in open lines. 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
12. Bxf3 Bxb1 13. cxb7 Nb6 14. Qxb6+ Ke8 15. Qxb1
Why it works
- Great move! bishop to f3 keeps the pressure (+2.6).
- Well found: pawn to b7 (+2.8).
- Strong! queen to b6 is the sharp choice (+3.1).
- Great move! queen to b1 keeps the pressure (+3.3).
- You win a piece — the rook.
- If instead Bxb1, then cxb7 and you stay on top.
Move by move
- 12. Bxf3 — bishop to f3 (capture)
- Bxb1 — bishop to b1 (capture)
- 13. cxb7 — pawn to b7 (capture)
- Nb6 — knight to b6
- 14. Qxb6+ — queen to b6 (capture) with check
- Ke8 — king to e8
- 15. Qxb1 — queen to b1 (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 #187.
SP-187 · ThroneScout — A central king (d or e), but with a knight posted out on the a- or h-file.
The king starts on d1, the rooks on b1 and f1, the queen on g1.
The kingside rook already stands on f1, so castling short moves only the king, from d1 to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneScout family; read right to left it becomes position 769.
The engine's main line opens with g4.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #187Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-187
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads