Winning blow: knight to c6 (b4·12)
c9-28487naming 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 1610 ShuffleRating — for advanced tacticians.
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 c2, queen b3, rook f1, knight b4 b5, pawn d2 e2 h2 g3 f4.
Black: king e8, queen a5, rook f8, bishop h8, knight f6, pawn f5 d6 e7 g7 h7.
10 white and 10 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
Material is level — 25 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on c2, the black king on e8.
It is White to move on move 20, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): a, b, c — 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
20. Nc6 Kd7 21. Nxa5
Why it works
- Great move! knight to c6 keeps the pressure (+7.2).
- Well found: knight to a5 (+7.7).
- You win a piece — the queen.
- If instead Kd7, then Nxa5 and you win the queen.
Move by move
- 20. Nc6 — knight to c6
- Kd7 — king to d7
- 21. Nxa5 — knight to a5 (capture)
Types in this puzzle
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #803.
SP-803 · BastionGuard — Off-centre king (c/f), no knight on the a- or h-file.
The king starts on c1, the rooks on b1 and f1, 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, h2.
The setup belongs to the BastionGuard family; read right to left it becomes position 147.
The engine's main line opens with g3.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #803Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-803
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