Winning blow: pawn to a4 (a2·3)
c9-09712naming 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 2060 ShuffleRating — expert level — few solve it at first try.
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, rook b7, pawn a2 f2 e3 g3 c4.
Black: king e8, pawn e4 g4 c5.
7 white and 4 black pieces are on the board; the puzzle position arises after move 38.
The position in numbers
White are ahead by 7 points of material (10 against 3; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c2, the black king on e8.
It is White to move on move 38, with 25 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 3. Files fully open (no pawns of either colour): b, d, h — natural highways for the rooks and queen.
The White king has 7 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
38. a4 Kd8 39. a5 Kc8 40. a6
Why it works
- Sensible development: pawn to a4.
- pawn to a5 develops smoothly.
- A natural move: pawn to a6.
- You win decisive material (+15.0).
- If instead Kf8, then a5 and you stay on top.
Move by move
- 38. a4 — pawn to a4
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?
Passed pawn
Nothing can stop the passer — escort it to the last rank.
A passed pawn has no enemy pawns in front of it or on the neighboring files: only pieces can stop it. Check who can blockade the pawn or catch it with the king — if nobody can, the pawn is worth a whole piece. Push the passer with your pieces supporting it, and put your rook behind it. The beginner's mistake is shoving the pawn forward unprotected, straight into a capture.
Rook endgame
The most common endgame — activity decides everything.
The rook endgame is the most common of all: rooks and pawns on the board. Its first law is activity — a rook behind a passed pawn beats a rook passively babysitting one. The sign of a correct plan is that your rook is attacking something, not guarding something. The typical error is locking your rook into defense: it is often better to give up a pawn and keep your rook and king active.
About this position
These pieces come from starting position #676.
SP-676 · ThroneGuard — A centre-file king with no knight on the edge; a position and its mirror twin always share this family.
The king starts on e1, the rooks on d1 and h1, the queen on a1.
The queenside rook already stands on d1, so castling long moves only the king, from e1 to c1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 478.
The engine's main line opens with b3.
Morozov Balance Index: 13 of 100 — class D — largest edge. Engine evaluation of the starting position: +41 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #676Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-676
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