Winning blow: bishop to b5 (a6·2)
c9-19503naming 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 1060 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 a1, rook h1 b4, bishop a6, knight c3 g3, pawn c2 d2 g2 h3 f4.
Black: king d7, queen a7, rook a8 h8, bishop e8, knight g4 d8, pawn b5 d5 e6 f7 g7 h7.
12 white and 13 black pieces are on the board; the puzzle position arises after move 16.
The position in numbers
Black are ahead by 1 points of material (33 against 34; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c1, the black king on d7.
It is White to move on move 16, with 43 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 — natural highways for the rooks and queen. Half-open for White: b, e.
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
16. Bxb5+ Kc7 17. Ra4 Qxa4 18. Bxa4
Why it works
- Great move! bishop to b5 keeps the pressure (+4.8).
- Spot on — rook to a4 (+4.7).
- Precise: bishop to a4 is the top choice (+4.6).
- You win a piece — the queen.
- If instead Kc7, then Ra4 and you stay on top.
Move by move
- 16. Bxb5+ — bishop to b5 (capture) with check
- Kc7 — king to c7
- 17. Ra4 — rook to a4
- Qxa4 — queen to a4 (capture)
- 18. Bxa4 — bishop to a4 (capture)
Types in this puzzle
Discovered attack
A piece steps aside and opens a second attack from the piece behind it.
A discovered attack works like a curtain: one piece steps off the line and unveils the long-range piece behind it. The beauty is that the moving piece can create a second threat of its own — two attacks in one move. Look for your stacked pairs: a bishop or rook behind a knight or pawn, aimed through them at something valuable. Send the front piece to the most aggressive square — a discovery without a second threat wastes half its power.
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.
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 #682.
SP-682 · BastionGuard — Both knights begin inside the board while the king stands on c or f; a position and its mirror twin share this family.
The king starts on c1, the rooks on b1 and h1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 469.
The engine's main line opens with a4.
Morozov Balance Index: 43 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +28 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #682Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-682
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