Winning blow: knight to d6 (b5·11)
c9-23641naming 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 g1, bishop e2, knight b5, pawn g2 h2 b3 c3 a4 e4 g5.
Black: king b7, queen g7, bishop g8, knight a6 d8, pawn a5 e5 b6 g6 h7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 26.
The position in numbers
Black are ahead by 1 points of material (22 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 26, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 5. Files fully open (no pawns of either colour): d, f — natural highways for the rooks and queen.
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
26. Nd6+ Kc6 27. Qd1 Qe7 28. Nc8 Qe6 29. Bxa6
Why it works
- Great move! knight to d6 keeps the pressure (+3.3).
- queen to d1 develops smoothly.
- Strong! knight to c8 is the sharp choice (+3.7).
- Great move! bishop to a6 keeps the pressure (+3.9).
- You win a piece — the knight.
- If instead Kc6, then Qd1 and you stay on top.
Move by move
- 26. Nd6+ — knight to d6 with check
- Kc6 — king to c6
- 27. Qd1 — queen to d1
- Qe7 — queen to e7
- 28. Nc8 — knight to c8
- Qe6 — queen to e6
- 29. Bxa6 — bishop to a6 (capture)
Types in this puzzle
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
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.
About this position
These pieces come from starting position #666.
SP-666 · BastionGuard — King off-centre on c or f with both knights on inner files.
The king starts on c1, the rooks on a1 and d1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on b2, c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 197.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #666Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-666
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