Winning blow: queen to a6 (e2·4)
c9-19087naming 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 1390 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 d1, queen e2, rook b1 e1, bishop a1 b7, knight h1 c3, pawn c2 g2 h2 b3 f3 a4 d4.
Black: king b8, queen g8, rook d8 e8, bishop a3, knight a7 h8, pawn e4 a5 f5 b6 e6 c7 g7 h7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
White are ahead by 2 points of material (38 against 36; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on b8.
It is White to move on move 16, with 36 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 8. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: e.
White 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. Qa6 Rxd4+ 17. Ke2 Rb4 18. Nb5 Rxb5 19. axb5
Why it works
- Sensible development: queen to a6.
- Spot on — king to e2 (+2.6).
- Strong! knight to b5 is the sharp choice (+4.8).
- Great move! pawn to b5 keeps the pressure (+4.7).
- You reach a winning position (+4.7).
- If instead Rxd4+, then Ke2 and you stay on top.
Move by move
- 16. Qa6 — queen to a6
- Rxd4+ — rook to d4 (capture) with check
- 17. Ke2 — king to e2
- Rb4 — rook to b4
- 18. Nb5 — knight to b5
- Rxb5 — rook to b5 (capture)
- 19. axb5 — pawn to b5 (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 #642.
SP-642 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on d1, the rooks on b1 and e1, the queen on g1.
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.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The pawn on c2, d2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 215.
The engine's main line opens with f4.
Morozov Balance Index: 75 of 100 — class B — balanced. Engine evaluation of the starting position: +19 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #642Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-642
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