Winning blow: king to a2 (b1·38)
c9-26665naming 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 b1, queen h3, rook a1, bishop d4 g4, knight b3 e6, pawn b2 c2 d2 a4.
Black: king b8, queen e1, rook d5, bishop g5 e8, knight h4 d6, pawn a5 b7 c7.
11 white and 10 black pieces are on the board; the puzzle position arises after move 21.
The position in numbers
White are ahead by 1 points of material (30 against 29; 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 b8.
It is White to move on move 21, with 3 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 4 pawns, Black 3. Files fully open (no pawns of either colour): e, f, g, h — natural highways for the rooks and queen.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
21. Ka2 Qe4 22. d3 Qg6 23. c4 Rxd4 24. Nbxd4
Why it works
- Great move! king to a2 keeps the pressure (+3.2).
- pawn to d3 develops smoothly.
- A natural move: pawn to c4.
- Best move. knight to d4 is exactly what the engine plays (+3.5).
- You reach a winning position (+3.5).
- If instead Qe4, then d3 and you stay on top.
Move by move
- 21. Ka2 — king to a2
- Qe4 — queen to e4
- 22. d3 — pawn to d3
- Qg6 — queen to g6
- 23. c4 — pawn to c4
- Rxd4 — rook to d4 (capture)
- 24. Nbxd4 — knight to d4 (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.
About this position
These pieces come from starting position #857.
SP-857 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on b1, the rooks on a1 and f1, 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 d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 105.
The engine's main line opens with a4.
Morozov Balance Index: 18 of 100 — class D — largest edge. Engine evaluation of the starting position: +38 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #857Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-857
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