Winning blow: knight to d4 (f3·8)
c9-27053naming 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 1560 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 b1, queen g6, rook a1, bishop e3, knight f3, pawn b2 g2 h2 c3 a4 e5.
Black: king a7, queen c7, rook a8 e8, bishop f8, pawn d4 a6 h6 b7 g7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 18.
The position in numbers
Black are ahead by 1 points of material (26 against 27; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on a7.
It is White to move on move 18, with 49 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: d.
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
18. Nxd4 Rad8 19. Nb5+ Kb8 20. Nxc7
Why it works
- Great move! knight to d4 keeps the pressure (+7.3).
- Spot on — knight to b5 (+7.8).
- Precise: knight to c7 is the top choice (+7.9).
- You win a piece — the queen.
- If instead Rad8, then Nb5+ and you stay on top.
Move by move
- 18. Nxd4 — knight to d4 (capture)
- Rad8 — rook to d8
- 19. Nb5+ — knight to b5 with check
- Kb8 — king to b8
- 20. Nxc7 — knight to c7 (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.
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.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #902.
SP-902 · RampartScout — The king starts on b or g while a knight begins on the a- or h-file — the smallest family.
The king starts on b1, the rooks on a1 and e1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartScout family; read right to left it becomes position 54.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 2 of 100 — class D — largest edge. Engine evaluation of the starting position: +62 centipawns for White (depth 48, 400 000 000 nodes).
In 50 self-play games White scored 54.0% (95% CI 40.4–67.0%).
Explore position #902Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-902
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