Chess960 tactic on b5 (b4)
c9-15244naming 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 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.
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 b2, queen b4, bishop c4 f6, pawn a2 h2 c3 b6.
Black: king c6, queen d1, bishop h6 h7, knight d2 c8, pawn f4 h5 d7 f7.
8 white and 10 black pieces are on the board; the puzzle position arises after move 32.
The position in numbers
Black are ahead by 6 points of material (19 against 25; pawn = 1, knight and bishop = 3, rook = 5, queen = 9) — the tactic has to convert or outweigh that.
The white king stands on b2, the black king on c6.
It is White to move on move 32, with 32 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 4 pawns, Black 4. Files fully open (no pawns of either colour): e, g — natural highways for the rooks and queen. Half-open for White: d, f.
The White king has 1 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
32. Qb5+ Kb7 33. Qxd7+ Kb8 34. Qc7+ Ka8 35. Qxc8#
Why it works
- Great move! queen to b5 keeps the pressure (#3).
- Spot on — queen to d7 (#2).
- Precise: queen to c7 is the top choice (#1).
- Best move. queen to c8 is exactly what the engine plays (#).
- The line ends in a forced mate in 4.
- If instead Kb7, then Qxd7+ and you stay on top.
Move by move
- 32. Qb5+ — queen to b5 with check
- Kb7 — king to b7
- 33. Qxd7+ — queen to d7 (capture) with check
- Kb8 — king to b8
- 34. Qc7+ — queen to c7 with check
- Ka8 — king to a8
- 35. Qxc8# — queen to c8 (capture) and it is checkmate
Types in this puzzle
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.
Only move
Everything else loses — find the only move that holds.
An only move is a position where everything loses except one single continuation. You cannot play "by hand" here: run through fundamentally different defenses — run away, block, trade, counterattack — and discard the ones that fail. The hallmark of these puzzles is that the obvious moves lose quickly while the solution often looks strange. First understand exactly what the threat is — then the one saving move reveals itself.
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 #607.
SP-607 · ThroneGuard — A central king (d or e) and two knights tucked onto inner files: the family that holds the standard array, SP-518.
The king starts on d1, the rooks on a1 and e1, the queen on b1.
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.
A bishop starts in the corner on h1: it has a single diagonal, which the g-pawn unlocks, running out to a8.
Every pawn on the second rank is defended from the very first move.
The setup belongs to the ThroneGuard family; read right to left it becomes position 256.
The engine's main line opens with e4, putting a pawn straight into the centre.
Morozov Balance Index: 34 of 100 — class C — noticeable edge. Engine evaluation of the starting position: +31 centipawns for White (depth 46, 400 000 000 nodes).
Explore position #607Provenance
Mined from the project's engine self-play games.
Pack 015 · SP-607
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