Winning blow: knight to d7 (c5·11)
c9-17220naming 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 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.
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, bishop h1 d4, knight c5, pawn a2 d2 h3 g4.
Black: king f8, queen f4, rook e8, bishop h8, knight b1 h6, pawn b6 f6 g6 a7 h7.
9 white and 11 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
Black are ahead by 6 points of material (22 against 28; 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 f8.
It is White to move on move 22, with 44 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 5. Files fully open (no pawns of either colour): c, e — natural highways for the rooks and queen. Half-open for White: b, f.
White hold the bishop pair, an edge in open lines. The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
22. Nd7+ Kg7 23. Nxf6+ Nf7 24. Nh5+ Kf8 25. Nxf4
Why it works
- Great move! knight to d7 keeps the pressure (+5.8).
- Spot on — knight to f6 (+5.8).
- Strong! knight to h5 is the sharp choice (+6.7).
- Great move! knight to f4 keeps the pressure (+7.4).
- You win a piece — the queen.
- If instead Kg7, then Nxf6+ and you stay on top.
Move by move
- 22. Nd7+ — knight to d7 with check
- Kg7 — king to g7
- 23. Nxf6+ — knight to f6 (capture) with check
- Nf7 — knight to f7
- 24. Nh5+ — knight to h5 with check
- Kf8 — king to f8
- 25. Nxf4 — knight to f4 (capture)
Types in this puzzle
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
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.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
About this position
These pieces come from starting position #643.
SP-643 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on d1, the rooks on b1 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 a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
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 211.
The engine's main line opens with g4.
Morozov Balance Index: 89 of 100 — class A — most balanced. Engine evaluation of the starting position: +14 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #643Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-643
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