Attack on the uncastled king: rook to b2 (b1·8)
c9-09736naming 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.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1010 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.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
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 d7, rook b1 f1, bishop h1, knight d2, pawn c2 h2 a4 c5.
Black: king b8, rook a8 e8, bishop b2 g8, knight c4, pawn d3 a5 d5 h6 b7.
10 white and 11 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 5 points of material (29 against 24; 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 b8.
It is White to move on move 24, with 2 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 4 pawns, Black 5. Files fully open (no pawns of either colour): e, f, g — natural highways for the rooks and queen. Half-open for White: b, d.
Black hold the bishop pair, an edge in open lines. 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
24. Rxb2 Nxb2 25. Qxe8+ Ka7 26. Qb5
Why it works
- Great move! rook to b2 keeps the pressure (+8.3).
- Spot on — queen to e8 (+9.0).
- Precise: queen to b5 is the top choice (+8.8).
- You win a piece — the rook.
- If instead Nxb2, then Qxe8+ and you win the rook.
Move by move
- 24. Rxb2 — rook to b2 (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.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
About this position
These pieces come from starting position #735.
SP-735 · RampartGuard — King pushed to the b- or g-file, knights off the edges — 144 positions here.
The king starts on b1, the rooks on a1 and f1, the queen on d1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
The pawn on b2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the RampartGuard family; read right to left it becomes position 416.
The engine's main line opens with a4.
Morozov Balance Index: 20 of 100 — class D — largest edge. Engine evaluation of the starting position: +37 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #735Provenance
Mined from the project's engine self-play games.
Pack 006 · SP-735
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