Chess960 tactic on b7 (c7·3)
c9-15606naming 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 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.
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 b1, queen f7, rook a1 c7, bishop a4 b6, pawn a2 g2 h2 e4.
Black: king b8, queen d8, rook a8, knight e2, pawn g7 h7.
10 white and 6 black pieces are on the board; the puzzle position arises after move 24.
The position in numbers
White are ahead by 10 points of material (29 against 19; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b1, 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 4 pawns, Black 2. Files fully open (no pawns of either colour): b, c, d, f — natural highways for the rooks and queen.
White 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
24. Rb7+ Kc8 25. Bxd8 Nc3+ 26. Kc2 Rxa4 27. Qc7#
Why it works
- Best move. rook to b7 is exactly what the engine plays (#3).
- Spot on — bishop to d8 (#2).
- A natural move: king to c2.
- Best move. queen to c7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kc8, then Bxd8 and you win the queen.
Move by move
- 24. Rb7+ — rook to b7 with check
- Kc8 — king to c8
- 25. Bxd8 — bishop to d8 (capture)
- Nc3+ — knight to c3 with check
- 26. Kc2 — king to c2
- Rxa4 — rook to a4 (capture)
- 27. 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.
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.
Counter-strike
Don't defend — answer the threat with a bigger one.
The counter-strike: instead of defending against the threat, you answer with a bigger threat of your own. While your opponent grabs a pawn, you deliver mate — the arithmetic favors you. Look for a counter when direct defenses fail: do you have a check, an attack on the queen, a mating threat? The beginner's error is meeting every threat with a reflexive defense without checking the counterattacking resources first.
About this position
These pieces come from starting position #813.
SP-813 · RampartScout — Wing king plus a rim knight, and only 72 positions qualify — the rarest pattern of all.
The king starts on b1, the rooks on a1 and f1, the queen on c1.
From b1 the king makes the longest journey Chess960 allows when castling short: five squares to g1.
The bishops stand on d1 and g1; their long diagonals reach h5 and a7 once the e- and f-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the RampartScout family; read right to left it becomes position 152.
The engine's main line opens with f4.
Morozov Balance Index: 69 of 100 — class B — balanced. Engine evaluation of the starting position: +21 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #813Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-813
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