Attack on the uncastled king: knight to b4 (d5·5)
c9-27999naming 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 1200 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 b1, queen e3, rook a1 h1, bishop h2 f3, knight d5, pawn c2 b3 a4 d4 g4 e5.
Black: king b8, queen e6, rook a8 e8, bishop h7 d8, knight d6, pawn b4 g5 c6 h6 b7 d7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 19.
The position in numbers
Material is level — 34 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on b1, the black king on b8.
It is White to move on move 19, with 39 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 6. Files fully open (no pawns of either colour): f — natural highways for the rooks and queen. Half-open for White: h.
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
19. Nxb4 Ba5 20. Nd3 Qe7 21. Kb2 Nc4+ 22. bxc4
Why it works
- Great move! knight to b4 keeps the pressure (+2.4).
- knight to d3 develops smoothly.
- Precise: king to b2 is the top choice (+2.6).
- Great move! pawn to c4 keeps the pressure (+4.3).
- You win a piece — the knight.
- If instead Ba5, then Nd3 and you stay on top.
Move by move
- 19. Nxb4 — knight to b4 (capture)
- Ba5 — bishop to a5
- 20. Nd3 — knight to d3
- Qe7 — queen to e7
- 21. Kb2 — king to b2
- Nc4+ — knight to c4 with check
- 22. bxc4 — pawn to c4 (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.
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 #749.
SP-749 · RampartGuard — A wing king (b/g) with no knight on the a- or h-file.
The king starts on b1, the rooks on a1 and h1, the queen on f1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
One second-rank pawn starts with no defender at all: d2.
The setup belongs to the RampartGuard family; read right to left it becomes position 408.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 4 of 100 — class D — largest edge. Engine evaluation of the starting position: +50 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #749Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-749
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads