Attack on the uncastled king: rook to d8 (d1·19)
c9-16595naming 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.
An opening trap from this Chess960 starting position.
A piece strikes across the board from its Chess960 starting square.
A fork made possible by the Chess960 piece placement.
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.
Early Chess960 traps punish natural but careless development. Look for a forcing move that exploits a piece the opponent has just placed on a poor square — a fork, a pin or a threat that wins material before either side is fully developed.
From some Chess960 setups a bishop or queen rakes a long diagonal straight from move one. Trace those long-range lines into the enemy camp: a single opened file or diagonal can create an immediate pin, skewer or mating threat.
A set-up fork needs one preparing move before the fork lands — a check that drives the king onto the forking square, or a capture that lines the targets up. Find the preparation first, then the fork it makes possible.
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 h1, rook a1 d1, bishop e1 f1, knight g1, pawn a2 b2 c2 e2 f2 h2 g4 e5.
Black: king c8, queen h8, rook a8 d8, bishop e8 f8, knight b8 g8, pawn a4 g5 b6 b7 f7 h7.
15 white and 14 black pieces are on the board; the puzzle position arises after move 7.
The position in numbers
Black are ahead by 1 points of material (36 against 37; 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 c8.
It is White to move on move 7, with 35 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 6. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen.
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
7. Rxd8+ Kxd8 8. Qxb7 Qxe5 9. O-O-O+ Bd6 10. Qxa8
Why it works
- Great move! rook to d8 keeps the pressure (+5.5).
- Well found: queen to b7 (+5.5).
- Precise: king to c1 is the top choice (+5.5).
- Best move. queen to a8 is exactly what the engine plays (+5.7).
- You win a piece — the rook.
- If instead Kxd8, then Qxb7 and you stay on top.
Move by move
- 7. Rxd8+ — rook to d8 (capture) with check
- Kxd8 — king to d8 (capture)
- 8. Qxb7 — queen to b7 (capture)
- Qxe5 — queen to e5 (capture)
- 9. O-O-O+ — king to a1 with check
- Bd6 — bishop to d6
- 10. Qxa8 — queen to a8 (capture)
Types in this puzzle
Long-range opener
From its unusual home square a long-range piece strikes across the board.
The long-range opener: a bishop, rook or queen strikes across the whole board straight from its starting area. In Chess960 the long-range pieces sit on unfamiliar squares, and a single pawn move can uncover a shot deep into the enemy camp. In the opening, trace with your eyes the diagonals and files of every long-range piece — yours and theirs. The mistake is pushing a pawn without checking whose line you have just opened.
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.
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.
About this position
These pieces come from starting position #666.
SP-666 · BastionGuard — King off-centre on c or f with both knights on inner files.
The king starts on c1, the rooks on a1 and d1, the queen on h1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on e1 and f1; their long diagonals reach a5 and a6 once the d- and e-pawns step aside.
The pawn on b2, c2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the BastionGuard family; read right to left it becomes position 197.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 40 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +29 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #666Provenance
Mined from the project's engine self-play games.
Pack 008 · SP-666
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