Winning blow: pawn to a3 (a2·3)
c9-28349naming 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 g1, queen a1, rook h1 e3, bishop b1, knight c3 f3, pawn a2 f2 g2 d4 h4 e5.
Black: king g8, queen b4, rook e8 f8, bishop g6 b8, knight h5, pawn a5 b6 f6 d7 e7 g7 h7.
13 white and 14 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
Black are ahead by 1 points of material (34 against 35; 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 16, with 31 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 7. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen. Half-open for White: b.
Black hold the bishop pair, an edge in open lines. 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
16. a3 Qxb1+ 17. Nxb1
Why it works
- Sensible development: pawn to a3.
- Well found: knight to b1 (+3.8).
- You win a piece — the queen.
- If instead Qxb1+, then Nxb1 and you win the queen.
Move by move
- 16. a3 — pawn to a3
- Qxb1+ — queen to b1 (capture) with check
- 17. Nxb1 — knight to b1 (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 #196.
SP-196 · 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 f1, the rooks on e1 and h1, the queen on a1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
The pawn on g2 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 670.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #196Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-196
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