Winning blow: king to a2 (b1·26)
c9-21754naming 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 1250 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 b1, rook a1 g7, pawn b2 a3 h3 f4 e5.
Black: king c6, rook d1 a6, pawn a4 c5 h5 b7.
8 white and 7 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 1 points of material (15 against 14; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, the black king on c6.
It is White to move on move 37, with 2 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): d, g — 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
37. Ka2 Rxa1+ 38. Kxa1 Kd5 39. Rxb7
Why it works
- Great move! king to a2 keeps the pressure (+2.6).
- Spot on — king to a1 (+2.8).
- Precise: rook to b7 is the top choice (+2.7).
- You reach a winning position (+2.7).
- If instead Rxa1+, then Kxa1 and you stay on top.
Move by move
- 37. Ka2 — king to a2
- Rxa1+ — rook to a1 (capture) with check
- 38. Kxa1 — king to a1 (capture)
- Kd5 — king to d5
- 39. Rxb7 — rook to b7 (capture)
Types in this puzzle
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
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.
King evacuation
The king walks out of the danger zone on its own feet.
King evacuation: when the shelter collapses, the king walks out of the attack on his own feet — sometimes across half the board. A series of precise king moves carries him out of the firing zone, and the enemy attack dissolves. The signs: no direct defense works, but there is a route over unattacked squares to a quiet corner. Calculate the entire journey in advance — a king stranded halfway usually dies there.
About this position
These pieces come from starting position #954.
SP-954 · RampartGuard — King on the wing (b/g) with both knights on inner files.
The king starts on b1, the rooks on a1 and c1, the queen on h1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
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 5.
The engine's main line opens with a4.
Morozov Balance Index: 61 of 100 — class B — balanced. Engine evaluation of the starting position: +23 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #954Provenance
Mined from the project's engine self-play games.
Pack 009 · SP-954
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