Chess960 tactic on d8 (d6)
c9-15950naming 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.
A fork made possible by the Chess960 piece placement.
Difficulty 2350 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.
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.
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 c2, queen d1, rook a1 d6, bishop a2 f2, knight a3 c5, pawn b2 h2 c3 g3 a4.
Black: king b8, queen g6, rook a8 h8, bishop c7 g8, knight f3, pawn h3 a5 f5 e6 b7.
13 white and 12 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 3 points of material (36 against 33; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on c2, the black king on b8.
It is White to move on move 24, with 51 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 5. Files fully open (no pawns of either colour): d — natural highways for the rooks and queen. Half-open for White: e, f.
The White king has 4 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
24. Rd8+ Ka7 25. Nb5+ Kb6 26. Rd6+ Bxd6 27. Qxd6#
Why it works
- Great move! rook to d8 keeps the pressure (#3).
- Spot on — knight to b5 (#2).
- Precise: rook to d6 is the top choice (#1).
- Best move. queen to d6 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Ka7, then Nb5+ and you stay on top.
Move by move
- 24. Rd8+ — rook to d8 with check
- Ka7 — king to a7
- 25. Nb5+ — knight to b5 with check
- Kb6 — king to b6
- 26. Rd6+ — rook to d6 with check
- Bxd6 — bishop to d6 (capture)
- 27. Qxd6# — queen to d6 (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.
Setup fork
The random setup allows a fork that classical chess never sees.
A setup fork is a double attack that exists only because of the unusual starting squares — in classical chess these targets never stand side by side. Look for pairs of undefended pieces on your opponent's back rank and for squares from which a knight or pawn hits both at once. Such forks usually appear within the first moves, before the pieces disperse. In every new position, note right away which starting pieces are defended by no one.
Royal fork
A fork with check: the king must move, and the second piece is lost.
A royal fork is a fork with check — one of the two targets is the king itself. The check must be answered first, so nobody is left to rescue the second piece. Look for squares where your piece gives check and simultaneously attacks an undefended queen or rook. It is the most reliable fork of all, because your opponent literally has no choice.
About this position
These pieces come from starting position #716.
SP-716 · BastionGuard — A c- or f-file king and two knights on inner files (b–g).
The king starts on c1, the rooks on a1 and h1, the queen on d1.
The king already stands on c1, so castling long moves only the rook, from a1 to d1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
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 BastionGuard family; read right to left it becomes position 444.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 37 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +30 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #716Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-716
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