Winning blow: rook to a8 (a1·2)
c9-17284naming 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 920 ShuffleRating — for beginners taking their first steps in Chess960 tactics.
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 c1, queen h3, rook a1 e1, bishop d1, knight d3, pawn c2 d2 f3 g3 h4 d5.
Black: king g8, queen f7, rook a8 f8, bishop b4, knight g6, pawn b5 e5 h5 c7 g7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 23.
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 c1, the black king on g8.
It is White to move on move 23, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 5. Files fully open (no pawns of either colour): a — natural highways for the rooks and queen. Half-open for White: b, e.
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
23. Rxa8 Rxa8 24. Nxb4
Why it works
- Great move! rook to a8 keeps the pressure (+4.1).
- Well found: knight to b4 (+4.0).
- You win a piece — the rook.
- If instead Rxa8, then Nxb4 and you win the rook.
Move by move
- 23. Rxa8 — rook to a8 (capture)
- Rxa8 — rook to a8 (capture)
- 24. Nxb4 — knight to b4 (capture)
Types in this puzzle
X-ray
A long-range piece acts through an enemy piece on the same line.
An X-ray lets a long-range piece act through an enemy piece standing on the same line — its power shines straight through. The square behind looks safe or defended, and that illusion is exactly what the tactic exploits. Check your rooks, bishops and queens: is a key square or a target hiding behind an enemy piece on their line? When counting captures on a square, include the X-ray attackers — they join the fight the moment the line opens.
About this position
These pieces come from starting position #945.
SP-945 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and e1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
A bishop starts in the corner on a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
The second rank carries 2 pawns with no defender at all: a2, f2.
The setup belongs to the BastionGuard family; read right to left it becomes position 11.
The engine's main line opens with f4.
Morozov Balance Index: 9 of 100 — class D — largest edge. Engine evaluation of the starting position: +44 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #945Provenance
Mined from the project's engine self-play games.
Pack 004 · SP-945
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