Winning blow: king to a2 (b1·42)
c9-18837naming 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 1470 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 a5, rook a3, bishop e3, pawn b2 c2 f2 h3 a4.
Black: king b8, queen h1, bishop e5, knight c5, pawn d6 g6 b7 f7 h7.
9 white and 9 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
White are ahead by 2 points of material (22 against 20; 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 20, 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 5 pawns, Black 5. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: d, g.
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
20. Ka2 Qd5+ 21. Rb3 Bd4 22. Qd8+
Why it works
- Great move! king to a2 keeps the pressure (+4.1).
- rook to b3 develops smoothly.
- Precise: queen to d8 is the top choice (+4.3).
- You reach a winning position (+4.3).
- If instead Qd5+, then Rb3 and you stay on top.
Move by move
- 20. Ka2 — king to a2
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
About this position
These pieces come from starting position #919.
SP-919 · RampartGuard — The king starts out on a wing file, b or g, with neither knight in a corner.
The king starts on b1, the rooks on a1 and d1, the queen on e1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on c2 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 34.
The engine's main line opens with a4.
Morozov Balance Index: 65 of 100 — class B — balanced. Engine evaluation of the starting position: +22 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #919Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-919
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