Attack on the uncastled king: bishop to f6 (d4·8)
c9-21947naming 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 in 2: the first move creates an unstoppable threat, the second delivers mate.
A fork made possible by the Chess960 piece placement.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Difficulty 1320 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.
Mate in two usually opens with a forcing move — a check, a capture or an unstoppable threat — that strips the king of squares or defenders, so the follow-up mate becomes unavoidable. Look for the first move that leaves the opponent only losing replies.
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.
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 d1, queen b2, rook b1, bishop d4 c6, pawn a2 e2 f2 h2 d3 g3 b4 d5.
Black: king d8, queen a7, rook c8 g8, bishop g2 h8, pawn g5 a6 b6 d6 h6 c7 f7.
13 white and 13 black pieces are on the board; the puzzle position arises after move 17.
The position in numbers
Black are ahead by 4 points of material (28 against 32; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on d1, the black king on d8.
It is White to move on move 17, with 37 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 8 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c.
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
17. Bf6+ Bxf6 18. Qxf6#
Why it works
- Great move! bishop to f6 keeps the pressure (#1).
- Well found: queen to f6 (#).
- The line ends in a forced mate in 2.
- If instead Bxf6, then Qxf6# and it is mate.
Move by move
- 17. Bf6+ — bishop to f6 with check
- Bxf6 — bishop to f6 (capture)
- 18. Qxf6# — queen to f6 (capture) and it is checkmate
Types in this puzzle
Mate in 2
A forced checkmate in two moves.
Mate in two: your move, any reply, then the mating blow. Start with the most forcing first moves — checks and sacrifices that shrink the opponent's options to almost nothing. Against every single reply you must have a mate ready, so check them all without exception. The common failure is analyzing the pretty defense and forgetting the boring one.
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.
Clearance
Clear your own piece out of the way — with tempo — for the decisive blow.
Clearance is about your own piece standing in the way of the decisive blow — so you move it aside, or even throw it away. The key is to clear with tempo: jump off with a check, a capture or a threat, giving the opponent no time to regroup. The telltale sign: you see a crushing queen or rook move, but one of your own pieces blocks the line or occupies the square. Do not cling to it — a clearance sacrifice usually costs less than a missed attack.
About this position
These pieces come from starting position #299.
SP-299 · ThroneGuard — King home on d or e, knights kept off the a- and h-files — the family of the standard starting array.
The king starts on d1, the rooks on c1 and f1, the queen on a1.
Castling long simply swaps the two pieces: the king on d1 and the rook on c1 trade places.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneGuard family; read right to left it becomes position 369.
The engine's main line opens with d3.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 48, 400 000 000 nodes).
Explore position #299Provenance
Mined from the project's engine self-play games.
Pack 010 · SP-299
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