Winning blow: king to b1 (b2·5)
c9-10807naming 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 1890 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 b2, queen c4, bishop c2 b6, pawn d2 h2 g3 e4 f5.
Black: king d6, queen e8, rook a2 h8, bishop h1, knight b7, pawn g5 f6 e7 h7.
9 white and 10 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
Black are ahead by 9 points of material (20 against 29; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on d6.
It is White to move on move 24, with 6 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): a, b, c — natural highways for the rooks and queen.
White hold the bishop pair, an edge in open lines. The White king has 5 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Kb1 Ra1+ 25. Kxa1 Qa8+ 26. Ba4 Qxa4+ 27. Qxa4
Why it works
- Great move! king to b1 keeps the pressure (+5.0).
- Spot on — king to a1 (+5.7).
- Strong! bishop to a4 is the sharp choice (+6.3).
- Great move! queen to a4 keeps the pressure (+6.5).
- You win a piece — the queen.
- If instead Ra1+, then Kxa1 and you win the rook.
Move by move
- 24. Kb1 — king to b1
- Ra1+ — rook to a1 with check
- 25. Kxa1 — king to a1 (capture)
- Qa8+ — queen to a8 with check
- 26. Ba4 — bishop to a4
- Qxa4+ — queen to a4 (capture) with check
- 27. Qxa4 — queen to a4 (capture)
Types in this puzzle
Overload
One defender guards two things — it cannot do both jobs.
Overloading exploits a defender with two jobs at once — guarding a piece and covering a mating square, for instance. It cannot do both: your first strike forces it to handle one duty and abandon the other. Find the overworked piece by asking what happens to each of its charges if it gets distracted. Then hit one target and collect the other — an overloaded defender only pretends to defend.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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 #268.
SP-268 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on d1, the rooks on c1 and h1, the queen on f1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
One second-rank pawn starts with no defender at all: b2.
The setup belongs to the ThroneScout family; read right to left it becomes position 604.
The engine's main line opens with c4.
Morozov Balance Index: 1 of 100 — class D — largest edge. Engine evaluation of the starting position: +58 centipawns for White (depth 43, 400 000 000 nodes).
In 50 self-play games White scored 58.0% (95% CI 44.2–70.6%).
Explore position #268Provenance
Mined from the project's engine self-play games.
Pack 014 · SP-268
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