Winning blow: knight to d6 (b5·9)
c9-09016naming 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 b2, queen e5, rook c5, knight b5, pawn h2 g3 e4.
Black: king b7, queen a5, rook d7 f8, pawn b6 e6 g7 h7.
7 white and 8 black pieces are on the board; the puzzle position arises after move 35.
The position in numbers
Black are ahead by 3 points of material (20 against 23; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on b7.
It is White to move on move 35, with 34 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 4. Files fully open (no pawns of either colour): a, c, d, f — natural highways for the rooks and queen. Half-open for White: b.
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
35. Nd6+ Rxd6 36. Qxg7+ Ka6 37. Rxa5+ bxa5 38. Qxf8
Why it works
- Great move! knight to d6 keeps the pressure (+4.8).
- Well found: queen to g7 (+5.0).
- Strong! rook to a5 is the sharp choice (+5.1).
- Great move! queen to f8 keeps the pressure (+5.2).
- You win a piece — the queen.
- If instead Rxd6, then Qxg7+ and you stay on top.
Move by move
- 35. Nd6+ — knight to d6 with check
- Rxd6 — rook to d6 (capture)
- 36. Qxg7+ — queen to g7 (capture) with check
- Ka6 — king to a6
- 37. Rxa5+ — rook to a5 (capture) with check
- bxa5 — pawn to a5 (capture)
- 38. Qxf8 — queen to f8 (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.
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
About this position
These pieces come from starting position #706.
SP-706 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
The king starts on c1, the rooks on b1 and h1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the BastionGuard family; read right to left it becomes position 439.
The engine's main line opens with Ngf3, bringing the knight out to f3.
Morozov Balance Index: 59 of 100 — class B — balanced. Engine evaluation of the starting position: +24 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #706Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-706
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