Chess960 tactic on b6 (d4)
c9-09930naming 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 g1, queen d4, rook b1 f1, knight g3 d5, pawn c2 f2 g2 b5 e5 h5.
Black: king b7, rook a7 d8, bishop h6 d7, knight h4 g6, pawn e4 f5 g7 h7.
12 white and 11 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
White are ahead by 5 points of material (31 against 26; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on g1, the black king on b7.
It is White to move on move 22, with 45 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 6 pawns, Black 4. Files fully open (no pawns of either colour): a, d — natural highways for the rooks and queen.
Black hold the bishop pair, an edge in open lines. 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
22. Qb6+ Kc8 23. Qxa7 Nf3+ 24. gxf3 Be3 25. Qc7#
Why it works
- Great move! queen to b6 keeps the pressure (#3).
- Spot on — queen to a7 (#2).
- Precise: pawn to f3 is the top choice (#1).
- Best move. queen to c7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kc8, then Qxa7 and you win the rook.
Move by move
- 22. Qb6+ — queen to b6 with check
- Kc8 — king to c8
- 23. Qxa7 — queen to a7 (capture)
- Nf3+ — knight to f3 with check
- 24. gxf3 — pawn to f3 (capture)
- Be3 — bishop to e3
- 25. Qc7# — queen to c7 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 #777.
SP-777 · BastionScout — Off-centre king plus a rim knight (a/h): 168 positions carry this shape.
The king starts on c1, the rooks on b1 and g1, the queen on a1.
The king already stands on c1, so castling long moves only the rook, from b1 to d1.
The bishops stand on d1 and e1; their long diagonals reach h5 and a5 once the e- and d-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the BastionScout family; read right to left it becomes position 185.
The engine's main line opens with b4.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 47, 400 000 000 nodes).
Explore position #777Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-777
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