Winning blow: rook to b8 (f8)
c9-10808naming 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 1870 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 c2, queen f2, rook f8, knight e6, pawn d2 b3 h5.
Black: king b5, queen g7, rook d5, pawn b4 c6 c7.
7 white and 6 black pieces are on the board; the puzzle position arises after move 39.
The position in numbers
White are ahead by 3 points of material (20 against 17; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c2, the black king on b5.
It is White to move on move 39, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 3 pawns, Black 3. Files fully open (no pawns of either colour): a, e, f, g — natural highways for the rooks and queen. Half-open for White: c.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
39. Rb8+ Ka6 40. Ra8+ Kb5 41. Qf1+
Why it works
- Great move! rook to b8 keeps the pressure (#4).
- Spot on — rook to a8 (#3).
- Precise: queen to f1 is the top choice (#2).
- You win decisive material (+15.0).
- If instead Ka6, then Ra8+ and you stay on top.
Move by move
- 39. Rb8+ — rook to b8 with check
Types in this puzzle
Winning blow
Find the strike that wins material by force.
A winning blow is a forced material gain that does not fit a single textbook motif. The general tactical recipe applies: spot loose pieces, an awkwardly placed king, overloaded lines. Go through the forcing moves in order of violence — checks, captures, threats — because most combinations start with one of them. Do not judge by feel: calculate the concrete line until the outcome is beyond doubt.
About this position
These pieces come from starting position #259.
SP-259 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on d1, the rooks on c1 and g1, the queen on f1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
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, h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 595.
The engine's main line opens with b3.
Morozov Balance Index: 98 of 100 — class A — most balanced. Engine evaluation of the starting position: +3 centipawns for White (depth 45, 400 000 000 nodes).
In 50 self-play games White scored 47.0% (95% CI 33.9–60.6%).
Explore position #259Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-259
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