Winning blow: queen to a6 (b7·4)
c9-24383naming 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 1430 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 d1, queen b7, rook a1, bishop h2 d3, knight h1, pawn e2 a4 d4 c5 f5.
Black: king a5, queen b2, rook a8 d8, bishop h5, knight a7, pawn h4 b6 f6 g7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 23.
The position in numbers
Black are ahead by 1 points of material (28 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 d1, the black king on a5.
It is White to move on move 23, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: b, g, h.
White 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
23. Qa6+ Kb4 24. Qxb6+ Kc3 25. Rc1+ Qxc1+ 26. Kxc1
Why it works
- Great move! queen to a6 keeps the pressure (+11.9).
- Spot on — queen to b6 (#15).
- Strong! rook to c1 is the sharp choice (#11).
- Best move. king to c1 is exactly what the engine plays (#9).
- You win a piece — the queen.
- If instead Kb4, then Qxb6+ and you stay on top.
Move by move
- 23. Qa6+ — queen to a6 with check
- Kb4 — king to b4
- 24. Qxb6+ — queen to b6 (capture) with check
- Kc3 — king to c3
- 25. Rc1+ — rook to c1 with check
- Qxc1+ — queen to c1 (capture) with check
- 26. Kxc1 — king to c1 (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.
Overload
One defender guards two things — it cannot do both jobs.
Overloading exploits a defender with two jobs at once — guarding a piece and covering a mating square, for instance. It cannot do both: your first strike forces it to handle one duty and abandon the other. Find the overworked piece by asking what happens to each of its charges if it gets distracted. Then hit one target and collect the other — an overloaded defender only pretends to defend.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #632.
SP-632 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on a1 and g1, the queen on f1.
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 b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
The second rank carries 2 pawns with no defender at all: b2, h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 237.
The engine's main line opens with c3.
Morozov Balance Index: 43 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +28 centipawns for White (depth 50, 400 000 000 nodes).
Explore position #632Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-632
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