Winning blow: king to a1 (b1·15)
c9-12777naming 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 h7, rook a7, bishop f1 g1, knight d3, pawn b2 g2 h2 c3 f3 d5.
Black: king b8, queen b3, rook a8 d8, knight c4, pawn a2 g5 d6 h6.
12 white and 9 black pieces are on the board; the puzzle position arises after move 29.
The position in numbers
White are ahead by 3 points of material (29 against 26; 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 29, 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 6 pawns, Black 4. Files fully open (no pawns of either colour): e — natural highways for the rooks and queen. Half-open for White: a.
White hold the bishop pair, an edge in open lines. 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
29. Ka1 Rxa7 30. Qxa7+
Why it works
- Great move! king to a1 keeps the pressure (+4.2).
- Well found: queen to a7 (+4.8).
- You reach a winning position (+4.8).
- If instead Rxa7, then Qxa7+ and you stay on top.
Move by move
- 29. Ka1 — king to a1
- Rxa7 — rook to a7 (capture)
- 30. Qxa7+ — queen to a7 (capture) with check
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.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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.
About this position
These pieces come from starting position #846.
SP-846 · RampartScout — King on the wing (b/g) with a knight on the rim (a/h) — the rarest family.
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.
The bishops stand on f1 and g1; their long diagonals reach a6 and a7 once the e- and f-pawns step aside.
The pawn on b2, c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartScout family; read right to left it becomes position 116.
The engine's main line opens with e4, putting a pawn straight into the centre.
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 #846Provenance
Mined from the project's engine self-play games.
Pack 007 · SP-846
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