Winning blow: queen to b4 (b8)
c9-23097naming 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.
A fork made possible by the Chess960 piece placement.
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.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 a1, queen b8, rook d1 f1, bishop g1 h1, knight c5, pawn a2 b2 h3 g4.
Black: king g8, rook c8 f8, bishop f4 e6, knight d2 b4, pawn a5 g6 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 28.
The position in numbers
White are ahead by 7 points of material (32 against 25; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on a1, the black king on g8.
It is White to move on move 28, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): c, d, e, f — natural highways for the rooks and queen.
The White king has 0 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
28. Qxb4 axb4 29. Nxe6 Nxf1 30. Rxf1
Why it works
- Great move! queen to b4 keeps the pressure (+4.9).
- Well found: knight to e6 (+4.8).
- Precise: rook to f1 is the top choice (+4.3).
- You reach a winning position (+4.3).
- If instead axb4, then Nxe6 and you stay on top.
Move by move
- 28. Qxb4 — queen to b4 (capture)
- axb4 — pawn to b4 (capture)
- 29. Nxe6 — knight to e6 (capture)
- Nxf1 — knight to f1 (capture)
- 30. Rxf1 — rook to f1 (capture)
Types in this puzzle
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
Defensive exchange
Trade off the attacker — the storm dies with it.
The defensive exchange: your opponent's attack runs on one specific piece — trade it off, and the storm dies down. Find the "engine" of the attack, the piece without which the mating threats stop working: usually the queen or an invading knight. Offer the trade even at a small cost — your king breathes, and the material comes back later. The mistake is greedily dodging the exchange and getting mated a pawn up.
About this position
These pieces come from starting position #223.
SP-223 · 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 c1 and f1, the queen on b1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on d2, e2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 640.
The engine's main line opens with f4.
Morozov Balance Index: 83 of 100 — class A — most balanced. Engine evaluation of the starting position: +16 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #223Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-223
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