Winning blow: pawn to b8 (b7·16)
c9-13625naming 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 2060 ShuffleRating — expert level — few solve it at first try.
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 a7, rook g2, bishop h3, pawn d4 f4 a6 b7.
Black: king f8, queen d7, bishop e8, pawn e4 d5 f5 c6.
8 white and 7 black pieces are on the board; the puzzle position arises after move 37.
The position in numbers
White are ahead by 5 points of material (21 against 16; 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 f8.
It is White to move on move 37, with 27 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): g, h — natural highways for the rooks and queen. Half-open for White: c, e.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
37. b8=Q Qxa7 38. Qxa7 Bf7 39. Qc5+
Why it works
- Sensible development: pawn to b8.
- Spot on — queen to a7 (#4).
- Precise: queen to c5 is the top choice (#4).
- You win a piece — the queen.
- If instead Qxa7, then Qxa7 and you win the queen.
Move by move
- 37. b8=Q — pawn to b8
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.
Promotion
The pawn reaches the last rank and becomes a queen — decisively.
Promotion turns a pawn on the last rank into a queen and rewrites the evaluation on the spot. In tactics the passer rarely walks in for free — usually a sacrifice clears its path. Count the tempi: how many moves does the pawn need, and can the defender stop it in time? And watch the promotion square itself — it must be out of enemy reach or won by force in your combination.
About this position
These pieces come from starting position #42.
SP-42 · RampartScout — King on the wing (b/g) with a knight on the rim (a/h) — the rarest family.
The king starts on g1, the rooks on d1 and h1, the queen on c1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
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: a2.
The setup belongs to the RampartScout family; read right to left it becomes position 917.
The engine's main line opens with c4.
Morozov Balance Index: 42 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +23 centipawns for White (depth 44, 400 000 000 nodes).
In 50 self-play games White scored 56.0% (95% CI 42.3–68.8%).
Explore position #42Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-42
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