Winning blow: king to b1 (c1·36)
c9-23291naming 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.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1390 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.
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 a5, rook d1 f1, bishop h1, knight b3 g6, pawn a2 c2 e2 d3 b4.
Black: king e8, queen c7, rook f8, bishop g5 h7, knight f5 b6, pawn c3 d7 e7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 4 points of material (33 against 29; 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 e8.
It is White to move on move 21, with 6 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 5 pawns, Black 3. Files fully open (no pawns of either colour): f, g, h — natural highways for the rooks and queen.
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
21. Kb1 Bxg6 22. e4 Bf4 23. Rxf4 Qxf4 24. exf5
Why it works
- Great move! king to b1 keeps the pressure (+3.6).
- pawn to e4 develops smoothly.
- Precise: rook to f4 is the top choice (+3.3).
- Best move. pawn to f5 is exactly what the engine plays (+3.5).
- You reach a winning position (+3.5).
- If instead Bxg6, then e4 and you stay on top.
Move by move
- 21. Kb1 — king to b1
- Bxg6 — bishop to g6 (capture)
- 22. e4 — pawn to e4
- Bf4 — bishop to f4
- 23. Rxf4 — rook to f4 (capture)
- Qxf4 — queen to f4 (capture)
- 24. exf5 — pawn to f5 (capture)
Types in this puzzle
Relative pin
A piece shields a more valuable one behind it — moving it loses material.
In a relative pin the piece shields not its king but something valuable behind it, usually the queen. Moving is legal but costly, because the piece behind falls. Look for three units on one line: your long-range piece, a cheaper enemy piece, and an expensive one hiding behind. Beware the classic trap — a relatively pinned piece can still move with check or a bigger threat, so verify before you cash in.
About this position
These pieces come from starting position #239.
SP-239 · ThroneScout — King in the middle of the rank, with a knight already committed to the corner.
The king starts on d1, the rooks on b1 and f1, the queen on c1.
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.
One second-rank pawn starts with no defender at all: a2.
The setup belongs to the ThroneScout family; read right to left it becomes position 624.
The engine's main line opens with f4.
Morozov Balance Index: 26 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +34 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #239Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-239
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