Winning blow: rook to a2 (b2)
c9-21337naming 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 g1, queen c7, rook b2, knight f1, pawn f3 h3 b4 c5.
Black: king h6, pawn a4 h5 g6.
8 white and 4 black pieces are on the board; the puzzle position arises after move 40.
The position in numbers
White are ahead by 18 points of material (21 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 g1, the black king on h6.
It is White to move on move 40, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 3. Files fully open (no pawns of either colour): d, e — natural highways for the rooks and queen. Half-open for White: a, g.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
40. Ra2 Kg5 41. Qd8+ Kh6 42. Rxa4
Why it works
- Sensible development: rook to a2.
- Spot on — queen to d8 (#4).
- Precise: rook to a4 is the top choice (#3).
- You win decisive material (+15.0).
- If instead a3, then Rxa3 and you stay on top.
Move by move
- 40. Ra2 — rook to a2
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 #438.
SP-438 · RampartGuard — King on the wing (b/g) with both knights on inner files.
The king starts on g1, the rooks on a1 and h1, the queen on e1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on c1 and f1; their long diagonals reach h6 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: c2.
The setup belongs to the RampartGuard family; read right to left it becomes position 710.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 26 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +34 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #438Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-438
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