Attack on the uncastled king: queen to b8 (b7·4)
c9-11339naming 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.
Mate: a forcing sequence that ends the game — the king has no escape.
Mate in 4: a forced checkmate in four moves — every reply is covered.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 2120 ShuffleRating — expert level — few solve it at first try.
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 is a forced mating attack. Start from the enemy king: which of its squares are already covered, and which move takes away the rest while keeping the king in check? Forcing moves — checks and captures — are what turn an attack into mate.
A mate in four is a longer forced net: each of your moves is a check or an irresistible threat, and the king is driven step by step to a square where it is finally trapped. Verify that the defender has exactly one reply at every branch.
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.
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 b7, rook g3, bishop e1 d3, knight f1, pawn f2 g2 e3 h4.
Black: king g8, queen a5, rook h8, bishop g4 b8, knight f6, pawn e5 h5 f7 g7.
10 white and 10 black pieces are on the board; the puzzle position arises after move 24.
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 g8.
It is White to move on move 24, with 43 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): a, b, c, d — natural highways for the rooks and queen.
The White king has 2 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Qxb8+ Bc8 25. Qxc8+ Qd8 26. Qxd8+ Ne8 27. Qxe8#
Why it works
- Great move! queen to b8 keeps the pressure (#3).
- Well found: queen to c8 (#2).
- Strong! queen to d8 is the sharp choice (#1).
- Best move. queen to e8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Bc8, then Qxc8+ and you win the bishop.
Move by move
- 24. Qxb8+ — queen to b8 (capture) with check
- Bc8 — bishop to c8
- 25. Qxc8+ — queen to c8 (capture) with check
- Qd8 — queen to d8
- 26. Qxd8+ — queen to d8 (capture) with check
- Ne8 — knight to e8
- 27. Qxe8# — queen to e8 (capture) and it is checkmate
Types in this puzzle
Mate in 4+
A long forced mating combination.
Mate in four or longer is a marathon of forcing moves where the grip must never loosen. The tools are the same: checks, double threats and sacrifices that deny the opponent a single free tempo. Do not juggle the whole tree at once — walk the main line all the way to mate first, then verify the side branches. If somewhere the defender finds one quiet move that holds, your very first move was wrong.
Win the pinned piece
The pinned piece cannot run — attack it again and win it.
A pinned piece cannot flee, which means you can win it outright by attacking it one more time. Count attackers against defenders: if you outnumber them, the piece is yours. The best extra attacker is a pawn, since it costs less than anything it might capture. Do not rush the capture — build up the pressure first, then harvest.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #420.
SP-420 · RampartGuard — King on the wing (b/g) with both knights on inner files.
The king starts on g1, the rooks on a1 and h1, the queen on e1.
The king already stands on its castled square, so castling short moves only the rook, from h1 to f1.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
The pawn on g2 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 734.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 47 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +27 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #420Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-420
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