Winning blow: rook to a5 (a3)
c9-24603naming 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 1700 ShuffleRating — for advanced tacticians.
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, rook a3 c8, bishop h1, knight b6, pawn f2 h2 e3 d4 h5.
Black: king a7, rook a5 f8, bishop e8 h8, pawn b5 d5 g5 e6 b7 f7.
10 white and 11 black pieces are on the board; the puzzle position arises after move 25.
The position in numbers
Black are ahead by 1 points of material (21 against 22; 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 a7.
It is White to move on move 25, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 6. Files fully open (no pawns of either colour): a, c — natural highways for the rooks and queen. Half-open for White: b, g.
Black hold the bishop pair, an edge in open lines. 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
25. Rxa5+ Kxb6 26. Raa8 Bf6 27. Rxe8 Rxe8 28. Rxe8
Why it works
- Great move! rook to a5 keeps the pressure (+5.6).
- rook to a8 develops smoothly.
- Precise: rook to e8 is the top choice (+6.5).
- Great move! rook to e8 keeps the pressure (+6.6).
- You win a piece — the rook.
- If instead Kxb6, then Raa8 and you stay on top.
Move by move
- 25. Rxa5+ — rook to a5 (capture) with check
- Kxb6 — king to b6 (capture)
- 26. Raa8 — rook to a8
- Bf6 — bishop to f6
- 27. Rxe8 — rook to e8 (capture)
- Rxe8 — rook to e8 (capture)
- 28. Rxe8 — rook to e8 (capture)
Types in this puzzle
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.
Winning exchange
A forced series of captures on one square ends in your favour.
A winning exchange is a forced series of captures on one square that leaves you ahead in material. It is pure arithmetic: count the attackers and defenders of the square and note the value of every piece in the queue. Capture in the right order — cheap pieces first, expensive ones later — or a winning trade turns into a losing one. The classic error is stopping the count halfway and missing the opponent's final recapture.
Battery
Two pieces stacked on one line — the front one strikes with double force.
A battery stacks two long-range pieces on one line — a queen behind a bishop on a diagonal, or doubled rooks on a file. The front piece strikes with double force: capture it, and the piece behind recaptures with even more pressure. The battery is ready when both pieces already stare at one point and only the front strike is missing. Build batteries in advance on lines leading to the king — the doubling itself often breeds the combination.
About this position
These pieces come from starting position #747.
SP-747 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
The king starts on b1, the rooks on a1 and g1, the queen on f1.
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.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the RampartGuard family; read right to left it becomes position 401.
The engine's main line opens with a4.
Morozov Balance Index: 75 of 100 — class B — balanced. Engine evaluation of the starting position: +19 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #747Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-747
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