Chess960 tactic on b7 (e4·5)
c9-14353naming 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 f2, queen b5, rook d1 e6, bishop e4 e7, knight h1, pawn h2 a3.
Black: king c8, queen c3, rook g8, bishop b8, knight b6, pawn a4 h6 b7 g7.
9 white and 9 black pieces are on the board; the puzzle position arises after move 29.
The position in numbers
White are ahead by 6 points of material (30 against 24; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on f2, the black king on c8.
It is White to move on move 29, with 67 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 2 pawns, Black 4. Files fully open (no pawns of either colour): c, d, e, f — natural highways for the rooks and queen. Half-open for White: b, g.
White hold the bishop pair, an edge in open lines. 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
29. Bxb7+ Kxb7 30. Rxb6+ Ka8 31. Qa6+ Ba7 32. Qb7#
Why it works
- Best move. bishop to b7 is exactly what the engine plays (#3).
- Well found: rook to b6 (#2).
- Precise: queen to a6 is the top choice (#1).
- Best move. queen to b7 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kxb7, then Rxb6+ and you stay on top.
Move by move
- 29. Bxb7+ — bishop to b7 (capture) with check
- Kxb7 — king to b7 (capture)
- 30. Rxb6+ — rook to b6 (capture) with check
- Ka8 — king to a8
- 31. Qa6+ — queen to a6 with check
- Ba7 — bishop to a7
- 32. Qb7# — queen to b7 and it is checkmate
Types in this puzzle
Supported queen mate
The queen delivers mate face to face, protected by a friend.
The supported queen mate is the most common pattern of all: the queen lands next to the king and mates because a friendly piece or pawn protects her. The king is helpless — capturing is impossible, and the queen covers every neighboring square herself. Hunt for a protected square beside the enemy king: a knight, bishop or pawn eyeing it turns her invasion into mate. Verify one thing — that the square really is defended, or the king eats her.
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.
Corner mate
Driven into the corner, the king runs out of squares.
The corner mate catches a king driven into the corner, where it has only three neighboring squares — all of them taken away or blocked. The corner is the worst home for a king, because the attacker needs to control the fewest squares there. Herd the king toward the corner with checks and never let it slip back toward the center. Cut off the escape routes before the final check, and the mate practically assembles itself.
About this position
These pieces come from starting position #788.
SP-788 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on e1, the rooks on a1 and g1, the queen on d1.
Castling ends where it always does: king to g1 and rook to f1 on the short side, king to c1 and rook to d1 on the long one.
The bishops stand on b1 and c1; their long diagonals reach h7 and h6 once the c- and d-pawns step aside.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneScout family; read right to left it becomes position 174.
The engine's main line opens with d4, putting a pawn straight into the centre.
Morozov Balance Index: 78 of 100 — class A — most balanced. Engine evaluation of the starting position: +18 centipawns for White (depth 45, 400 000 000 nodes).
Explore position #788Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-788
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