Winning blow: rook to a4 (a3)
c9-18368naming 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 1200 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 b2, rook d1 a3, bishop h3, knight c7, pawn d2 g2 h2 b3 e4.
Black: king a7, queen a4, rook e7 d8, bishop g8, knight h4, pawn d4 g5 b6 b7 h7.
10 white and 11 black pieces are on the board; the puzzle position arises after move 27.
The position in numbers
Black are ahead by 9 points of material (21 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 b2, the black king on a7.
It is White to move on move 27, with 32 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): a, c, f — natural highways for the rooks and queen.
The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
27. Rxa4+ Kb8 28. Ra8+ Kxc7 29. Rc1+ Kd6 30. Rxd8+
Why it works
- Great move! rook to a4 keeps the pressure (+6.0).
- Well found: rook to a8 (+6.2).
- Strong! rook to c1 is the sharp choice (+6.3).
- Best move. rook to d8 is exactly what the engine plays (+6.2).
- You win a piece — the queen.
- If instead Kb8, then Ra8+ and you win the queen.
Move by move
- 27. Rxa4+ — rook to a4 (capture) with check
- Kb8 — king to b8
- 28. Ra8+ — rook to a8 with check
- Kxc7 — king to c7 (capture)
- 29. Rc1+ — rook to c1 with check
- Kd6 — king to d6
- 30. Rxd8+ — rook to d8 (capture) with check
Types in this puzzle
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
About this position
These pieces come from starting position #845.
SP-845 · RampartScout — King on b or g with a knight already on the edge — the least common of the position families (72 in all).
The king starts on b1, the rooks on a1 and e1, the queen on f1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the RampartScout family; read right to left it becomes position 120.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 5 of 100 — class D — largest edge. Engine evaluation of the starting position: +49 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #845Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-845
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