Winning blow: king to b4 (c4)
c9-27880naming 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 1390 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 c4, queen e4, rook d3, pawn a3 g3 h4 b5 f5.
Black: king b8, queen c2, rook h7, pawn a4 h5 f6 c7.
8 white and 7 black pieces are on the board; the puzzle position arises after move 39.
The position in numbers
White are ahead by 1 points of material (19 against 18; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c4, the black king on b8.
It is White to move on move 39, with 4 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): d, e — 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. Kb4 Ka7 40. Ka5 Qc5 41. Rd8 Qb6+ 42. Kxa4
Why it works
- Great move! king to b4 keeps the pressure (+3.3).
- king to a5 develops smoothly.
- Precise: rook to d8 is the top choice (+3.3).
- Great move! king to a4 keeps the pressure (+3.7).
- You reach a winning position (+3.7).
- If instead Ka7, then Ka5 and you stay on top.
Move by move
- 39. Kb4 — king to b4
- Ka7 — king to a7
- 40. Ka5 — king to a5
- Qc5 — queen to c5
- 41. Rd8 — rook to d8
- Qb6+ — queen to b6 with check
- 42. Kxa4 — king to a4 (capture)
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.
King evacuation
The king walks out of the danger zone on its own feet.
King evacuation: when the shelter collapses, the king walks out of the attack on his own feet — sometimes across half the board. A series of precise king moves carries him out of the firing zone, and the enemy attack dissolves. The signs: no direct defense works, but there is a route over unattacked squares to a quiet corner. Calculate the entire journey in advance — a king stranded halfway usually dies there.
About this position
These pieces come from starting position #705.
SP-705 · 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 h1, the queen on e1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
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, g2.
The setup belongs to the BastionGuard family; read right to left it becomes position 443.
The engine's main line opens with f4.
Morozov Balance Index: 24 of 100 — class D — largest edge. Engine evaluation of the starting position: +35 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #705Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-705
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