Chess960 tactic on b6 (e3·3)
c9-14830naming 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 2400 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 f1, queen e3, rook b1 g8, knight e2, pawn d3 c4 f4 h4 e6.
Black: king c7, queen a3, rook a2, bishop c6, pawn f5 h5 b7 e7.
10 white and 8 black pieces are on the board; the puzzle position arises after move 33.
The position in numbers
White are ahead by 6 points of material (27 against 21; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f1, the black king on c7.
It is White to move on move 33, with 47 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 5 pawns, Black 4. Files fully open (no pawns of either colour): a, g — natural highways for the rooks and queen. Half-open for White: b.
The White king has 3 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
33. Qb6+ Kd6 34. Qd8+ Bd7 35. Qxd7+ Kc5 36. Rc8#
Why it works
- Great move! queen to b6 keeps the pressure (#3).
- Well found: queen to d8 (#2).
- Precise: queen to d7 is the top choice (#1).
- Best move. rook to c8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kd6, then Qd8+ and you stay on top.
Move by move
- 33. Qb6+ — queen to b6 with check
- Kd6 — king to d6
- 34. Qd8+ — queen to d8 with check
- Bd7 — bishop to d7
- 35. Qxd7+ — queen to d7 (capture) with check
- Kc5 — king to c5
- 36. Rc8# — rook to c8 and it is checkmate
Types in this puzzle
Ladder mate
Two heavy pieces climb line by line, cutting off every retreat.
The ladder mate uses two heavy pieces climbing rung by rung: one cuts the king off along a line, the other checks on the next line, driving him toward the edge. It is the classic two-rook technique — check, the king retreats one rank, the other rook checks, until mate on the last rank. The only danger is the king creeping close enough to attack one of your rooks. If it does, simply slide that rook to the far side of the same line.
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.
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.
About this position
These pieces come from starting position #189.
SP-189 · ThroneScout — Centre-file king, rim knight: 204 of the 960 positions share this pattern.
The king starts on e1, the rooks on b1 and f1, the queen on h1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
The pawn on d2 is defended by the king alone — the same soft spot f2 is in the classical setup.
The setup belongs to the ThroneScout family; read right to left it becomes position 776.
The engine's main line opens with Nab3, bringing the knight out to b3.
Morozov Balance Index: 61 of 100 — class B — balanced. Engine evaluation of the starting position: +23 centipawns for White (depth 44, 400 000 000 nodes).
Explore position #189Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-189
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