Winning blow: king to a2 (b1·19)
c9-15259naming 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 1110 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 a6, rook a4 d7, knight g3 b5, pawn b2 c2 g2 h2 a3 f3.
Black: king b8, queen c5, rook e1 g8, bishop g7, knight c6, pawn f5 g5 b6 a7 h7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 26.
The position in numbers
White are ahead by 1 points of material (31 against 30; 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 26, 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 6 pawns, Black 5. Files fully open (no pawns of either colour): d, e — 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
26. Ka2 Ra1+ 27. Kxa1
Why it works
- Great move! king to a2 keeps the pressure (+9.7).
- Well found: king to a1 (#6).
- You win a piece — the rook.
- If instead Ra1+, then Kxa1 and you win the rook.
Move by move
- 26. Ka2 — king to a2
- Ra1+ — rook to a1 with check
- 27. Kxa1 — king to a1 (capture)
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.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
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 #630.
SP-630 · ThroneScout — King on a central file (d/e) with a knight starting on the rim (a/h).
The king starts on d1, the rooks on a1 and g1, the queen on e1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
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: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 230.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 3 of 100 — class D — largest edge. Engine evaluation of the starting position: +51 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #630Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-630
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