Winning blow: knight to a3 (b1·2)
c9-09425naming 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 g1, queen a1, rook c1 b6, bishop f1 d2, knight b1 d1, pawn b2 e2 f2 g2 h4 d5.
Black: king g8, queen a8, rook f6 a7, bishop e8 f8, knight d8, pawn d4 h5 c6 f7 g7.
14 white and 12 black pieces are on the board; the puzzle position arises after move 13.
The position in numbers
White are ahead by 4 points of material (37 against 33; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on g8.
It is White to move on move 13, with 42 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): a — natural highways for the rooks and queen. Half-open for White: c.
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
13. Na3 Bd7 14. e4 Bd6 15. Bg5
Why it works
- Great move! knight to a3 keeps the pressure (+3.3).
- pawn to e4 develops smoothly.
- A natural move: bishop to g5.
- You reach a winning position (+3.5).
- If instead Bd7, then e4 and you stay on top.
Move by move
- 13. Na3 — knight to a3
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?
Development punish
Half the army still asleep — the attack breaks through.
Punishing lazy development: half of your opponent's army is asleep on its starting squares, which means you outnumber him where the fight is. Count not the pieces on the board but the pieces in play — if five or more of his pieces have never moved, look for a forcing attack. The sign is a development lead plus open lines toward his king. Strike immediately: give him two quiet moves and the advantage evaporates.
About this position
These pieces come from starting position #106.
SP-106 · RampartGuard — Both knights begin on inner files while the king sits on the wing (b/g); mirror twins stay together in this family.
The king starts on g1, the rooks on c1 and h1, the queen on a1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the RampartGuard family; read right to left it becomes position 853.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 51 of 100 — class B — balanced. Engine evaluation of the starting position: +26 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #106Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-106
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