Winning blow: queen to b5 (g5)
c9-14557naming 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 1060 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 g5, rook a1 f2, bishop c3, pawn a2 b2 c2 h2 d3.
Black: king b7, queen e7, rook f8, bishop d7, knight e4 c6, pawn g4 h5 c7.
10 white and 9 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 1 points of material (27 against 26; 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 b7.
It is White to move on move 24, with 52 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 3. Files fully open (no pawns of either colour): e, f — natural highways for the rooks and queen. Half-open for White: g.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Qb5+ Kc8 25. Rxf8+ Qxf8 26. dxe4
Why it works
- Great move! queen to b5 keeps the pressure (+2.6).
- Spot on — rook to f8 (+3.2).
- Precise: pawn to e4 is the top choice (+3.0).
- You win a piece — the rook.
- If instead Kc8, then Rxf8+ and you win the rook.
Move by move
- 24. Qb5+ — queen to b5 with check
- Kc8 — king to c8
- 25. Rxf8+ — rook to f8 (capture) with check
- Qxf8 — queen to f8 (capture)
- 26. dxe4 — pawn to e4 (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.
Deflection
Force the defender away from its duty — then strike what it guarded.
Deflection forces the guard to leave its post: a sacrifice or exchange drags it away from the piece or square it protects. First find the critical defender — the piece whose absence makes the mate or the material win possible. Then find the move it cannot ignore, which is usually a capture. Do not be stingy: if removing the guard wins the queen or mates, the sacrifice pays for itself many times over.
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.
About this position
These pieces come from starting position #647.
SP-647 · ThroneGuard — King home on d or e, knights kept off the a- and h-files — the family of the standard starting array.
The king starts on d1, the rooks on a1 and e1, 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.
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: h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 210.
The engine's main line opens with f4.
Morozov Balance Index: 86 of 100 — class A — most balanced. Engine evaluation of the starting position: +15 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #647Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-647
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