Winning blow: rook to b5 (a5·3)
c9-25362naming 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 1610 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 a1, queen b3, rook g1 a5, bishop e1 f1, pawn b2 f2 g2 e3 a4 d6.
Black: king b8, queen b7, rook d8 g8, bishop g7, knight g6, pawn h2 g5 e6 c7 d7 h7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 20.
The position in numbers
Material is level — 31 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on a1, the black king on b8.
It is White to move on move 20, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c, h.
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
20. Rb5 Ka8 21. Rxb7
Why it works
- Great move! rook to b5 keeps the pressure (+5.8).
- Well found: rook to b7 (+6.3).
- You win a piece — the queen.
- If instead Ka8, then Rxb7 and you win the queen.
Move by move
- 20. Rb5 — rook to b5
- Ka8 — king to a8
- 21. Rxb7 — rook to b7 (capture)
Types in this puzzle
Absolute pin
A piece is pinned against its king — it cannot legally move.
An absolute pin freezes a piece on the line between its own king and your long-range attacker: moving it is simply illegal. The pattern is three units on one straight line — your bishop, rook or queen, an enemy piece, and the enemy king behind it. A pinned piece neither attacks nor defends anything: treat it as if it were off the board. Pile up on it, ideally with a pawn, because running away is against the rules.
Queen trap
The strongest piece ventures too far — and cannot come back.
A queen trap catches the strongest piece after it ventures too far and finds no way home. The usual story is a queen grabbing a distant pawn — the classic poisoned pawn. The warning signs: the queen has few retreat squares, and enemy minor pieces cut them off one by one, gaining tempo with every move. Before your queen snacks on a pawn in enemy territory, count her escape routes — fewer than two means stay home.
Quiet move
No check, no capture — yet this modest move decides the game.
A quiet move gives no check and takes nothing — yet it decides the game by creating an unstoppable threat or stealing the king's last square. This is the hardest class of moves: the eye hunts for loud blows while a modest shift does the winning. The clue: every forcing try runs into a defense, so seek the move that strengthens the threat or takes squares away. Train yourself to ask: what if I neither capture nor check, but quietly improve?
About this position
These pieces come from starting position #586.
SP-586 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on d1, the rooks on b1 and g1, the queen on a1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 277.
The engine's main line opens with b4.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 40, 400 000 000 nodes).
Explore position #586Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-586
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