Winning blow: pawn to b8 (b7·12)
c9-12708naming 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 g1, queen c7, rook f1, bishop a1, knight g2, pawn e2 f2 h2 d3 a4 b4 b7.
Black: king g7, queen h3, rook d5 h8, bishop h6, pawn d4 g4 e5 g6 f7.
12 white and 10 black pieces are on the board; the puzzle position arises after move 30.
The position in numbers
Material is level — 27 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on g1, the black king on g7.
It is White to move on move 30, with 38 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 5. Files fully open (no pawns of either colour): c — natural highways for the rooks and queen. Half-open for White: g.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
30. b8=Q Rxb8 31. Qxb8
Why it works
- Great move! pawn to b8 keeps the pressure (+4.1).
- Well found: queen to b8 (+3.9).
- You win a piece — the rook.
- If instead Rxb8, then Qxb8 and you win the rook.
Move by move
- 30. b8=Q — pawn to b8
- Rxb8 — rook to b8 (capture)
- 31. Qxb8 — queen to b8 (capture)
Types in this puzzle
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 #115.
SP-115 · BastionGuard — The king starts one file off-centre, on c or f, with neither knight in a corner.
The king starts on f1, the rooks on d1 and g1, the queen on c1.
Castling short simply swaps the two pieces: the king on f1 and the rook on g1 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 BastionGuard family; read right to left it becomes position 835.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 94 of 100 — class A — most balanced. Engine evaluation of the starting position: +10 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #115Provenance
Mined from the project's engine self-play games.
Pack 011 · SP-115
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads