Attack on the uncastled king: knight to f6 (e4·14)
c9-25551naming 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.
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.
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.
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 e2, rook a1 c2, bishop g1 h1, knight e4, pawn b2 d2 h2 b4.
Black: king d8, queen f6, rook b5 e8, bishop f4 g8, pawn g5 e6 a7 c7 d7 h7.
10 white and 12 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
Black are ahead by 8 points of material (23 against 31; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on e2, the black king on d8.
It is White to move on move 20, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 6. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: a, c, e, g.
The White king has 6 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
20. Nxf6 Re5+ 21. Be3 Rf8 22. Nxg8 Rxg8 23. Rxa7
Why it works
- Great move! knight to f6 keeps the pressure (+3.5).
- bishop to e3 develops smoothly.
- Precise: knight to g8 is the top choice (+3.5).
- Best move. rook to a7 is exactly what the engine plays (+3.7).
- You win a piece — the queen.
- If instead Re5+, then Be3 and you win the queen.
Move by move
- 20. Nxf6 — knight to f6 (capture)
- Re5+ — rook to e5 with check
- 21. Be3 — bishop to e3
- Rf8 — rook to f8
- 22. Nxg8 — knight to g8 (capture)
- Rxg8 — rook to g8 (capture)
- 23. Rxa7 — rook to a7 (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.
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.
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.
About this position
These pieces come from starting position #95.
SP-95 · ThroneScout — King in the middle of the rank, with a knight already committed to the corner.
The king starts on d1, the rooks on c1 and e1, the queen on f1.
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 second rank carries 2 pawns with no defender at all: a2, b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 864.
The engine's main line opens with g3.
Morozov Balance Index: 13 of 100 — class D — largest edge. Engine evaluation of the starting position: +41 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #95Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-95
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