Winning blow: bishop to a5 (e1·2)
c9-25316naming 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 c1, queen b5, rook d1 f1, bishop e1 h1, pawn e2 b3 g3 a4 c4 h4.
Black: king c7, queen a7, rook d8 f8, bishop g6 h8, pawn a5 c5 f5 d6 e7 h7.
12 white and 12 black pieces are on the board; the puzzle position arises after move 23.
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 c1, the black king on c7.
It is White to move on move 23, with 40 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: d, f.
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
23. Bxa5+ Kc8 24. Qc6+ Kb8 25. Bc7+ Kc8 26. Bxd6+
Why it works
- Great move! bishop to a5 keeps the pressure (#4).
- Spot on — queen to c6 (#3).
- Precise: bishop to c7 is the top choice (#2).
- Best move. bishop to d6 is exactly what the engine plays (#1).
- You win decisive material (+15.0).
- If instead Kc8, then Qc6+ and you stay on top.
Move by move
- 23. Bxa5+ — bishop to a5 (capture) with check
- Kc8 — king to c8
- 24. Qc6+ — queen to c6 with check
- Kb8 — king to b8
- 25. Bc7+ — bishop to c7 with check
- Kc8 — king to c8
- 26. Bxd6+ — bishop to d6 (capture) with check
Types in this puzzle
Relative pin
A piece shields a more valuable one behind it — moving it loses material.
In a relative pin the piece shields not its king but something valuable behind it, usually the queen. Moving is legal but costly, because the piece behind falls. Look for three units on one line: your long-range piece, a cheaper enemy piece, and an expensive one hiding behind. Beware the classic trap — a relatively pinned piece can still move with check or a bigger threat, so verify before you cash in.
Discovered check
The moving piece opens a check — and is free to grab anything meanwhile.
With a discovered check the moving piece unmasks a check from the piece standing behind it. While the king deals with the check, the piece that moved grabs whatever it likes, free of charge. Look for your long-range piece on a line with the enemy king, with exactly one of your own pieces in between. The rule: among all the ways to step aside, pick the one that captures or attacks the most expensive loot.
Check chase
Every move is a check — the king is chased into losing ground.
In a check chase every one of your moves is a check, so the opponent never gets a free second. The king is herded across the board until it loses a piece or walks into a decisive blow. Such lines are the easiest to calculate: each check allows only a handful of replies, so try them all. Make it a habit to start calculating any sharp position with the checks — they are the most forcing moves on the board.
About this position
These pieces come from starting position #687.
SP-687 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and f1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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: e2.
The setup belongs to the BastionGuard family; read right to left it becomes position 464.
The engine's main line opens with f4.
Morozov Balance Index: 21 of 100 — class D — largest edge. Engine evaluation of the starting position: +36 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #687Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-687
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