Winning blow: rook to a8 (a1·11)
c9-19930naming 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 g1, queen f3, rook a1 f1, bishop d3 e3, pawn d2 g2 h2 f4.
Black: king c8, queen d6, rook b7 d8, knight d4 f6, pawn f5 g6 c7 d7 h7.
10 white and 11 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
Black are ahead by 1 points of material (29 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 g1, the black king on c8.
It is White to move on move 24, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 5. Files fully open (no pawns of either colour): a, b, e — natural highways for the rooks and queen. Half-open for White: c.
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
24. Ra8+ Rb8 25. Rxb8+ Kxb8 26. Rb1+ Qb6 27. Rxb6+
Why it works
- Great move! rook to a8 keeps the pressure (+7.7).
- Well found: rook to b8 (+8.0).
- Strong! rook to b1 is the sharp choice (+8.3).
- Best move. rook to b6 is exactly what the engine plays (+8.3).
- You win a piece — the queen.
- If instead Rb8, then Rxb8+ and you win the rook.
Move by move
- 24. Ra8+ — rook to a8 with check
- Rb8 — rook to b8
- 25. Rxb8+ — rook to b8 (capture) with check
- Kxb8 — king to b8 (capture)
- 26. Rb1+ — rook to b1 with check
- Qb6 — queen to b6
- 27. Rxb6+ — rook to b6 (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.
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.
Remove the defender
Capture the guard first — then take what it protected.
Removing the defender is the straightforward plan: capture the guard first, then take what it guarded. Unlike deflection, the defender is not lured away — it is traded off or destroyed on the spot. Stare at the target you crave and ask who defends it, and whether that defender can be profitably eaten. Count the whole capture sequence, not just the first move — the trade must pay off at the end.
About this position
These pieces come from starting position #728.
SP-728 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on c1, the rooks on a1 and h1, the queen on f1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and e1; their long diagonals reach h7 and a5 once the c- and d-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionGuard family; read right to left it becomes position 429.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 61 of 100 — class B — balanced. Engine evaluation of the starting position: +23 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #728Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-728
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