Chess960 tactic on c4 (b3·2)
c9-16319naming 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.
Difficulty 2120 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.
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 a1, rook b1 h1, bishop e1 h5, knight b8, pawn f2 h2 b3 g3 a4 d6 e7.
Black: king g8, queen c4, rook h8, bishop b6, pawn b4 a5 c5 f6 g7 h7.
14 white and 10 black pieces are on the board; the puzzle position arises after move 22.
The position in numbers
White are ahead by 12 points of material (35 against 23; 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 g8.
It is White to move on move 22, with 6 legal replies to weigh — only the line that keeps the advantage solves the puzzle. White are in check right now, so every reply must answer the check.
White keeps 7 pawns, Black 6. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c.
White hold the bishop pair, an edge in open lines. 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
22. bxc4 g5 23. e8=Q+ Kg7 24. Qf7+ Kh6 25. Qaxf6#
Why it works
- Best move. pawn to c4 is exactly what the engine plays (#2).
- Spot on — pawn to e8 (#2).
- Precise: queen to f7 is the top choice (#1).
- Best move. queen to f6 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead g5, then e8=Q+ and you win the queen.
Move by move
- 22. bxc4 — pawn to c4 (capture)
- g5 — pawn to g5
- 23. e8=Q+ — pawn to e8 with check
- Kg7 — king to g7
- 24. Qf7+ — queen to f7 with check
- Kh6 — king to h6
- 25. Qaxf6# — queen to f6 (capture) 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.
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.
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 #681.
SP-681 · BastionGuard — King shifted to c or f, knights kept clear of the edges — 168 positions in all.
The king starts on c1, the rooks on b1 and h1, 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.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the BastionGuard family; read right to left it becomes position 473.
The engine's main line opens with b4.
Morozov Balance Index: 10 of 100 — class D — largest edge. Engine evaluation of the starting position: +43 centipawns for White (depth 42, 400 000 000 nodes).
Explore position #681Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-681
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