Mate in 3: queen to c7 (c4)
c9-11064naming 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 in 3: a forced sequence that ends in checkmate.
A fork made possible by the Chess960 piece placement.
Difficulty 1860 ShuffleRating — for advanced tacticians.
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.
In a mate in three every move must be forcing; the defender should never get a free tempo. Find the check or threat that herds the king, calculate the single defence to each, and confirm the net closes on the third move.
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 c1, queen c4, knight h1 b5, pawn a2 g3.
Black: king b8, queen h2, rook d8, bishop b7, knight g6, pawn f4 f6 g7 h7.
6 white and 9 black pieces are on the board; the puzzle position arises after move 35.
The position in numbers
Black are ahead by 7 points of material (17 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 c1, the black king on b8.
It is White to move on move 35, with 31 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): b, c, d, e — natural highways for the rooks and queen. Half-open for White: f, h.
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
35. Qc7+ Ka8 36. Qxd8+ Bc8 37. Qxc8#
Why it works
- Great move! queen to c7 keeps the pressure (#2).
- Spot on — queen to d8 (#1).
- Strong! queen to c8 is the sharp choice (#).
- The line ends in a forced mate in 3.
- If instead Ka8, then Qxd8+ and you win the rook.
Move by move
- 35. Qc7+ — queen to c7 with check
- Ka8 — king to a8
- 36. Qxd8+ — queen to d8 (capture) with check
- Bc8 — bishop to c8
- 37. 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.
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.
About this position
These pieces come from starting position #626.
SP-626 · ThroneScout — The king starts on d or e while at least one knight begins in a corner.
The king starts on d1, the rooks on b1 and g1, the queen on e1.
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 a1: it has a single diagonal, which the b-pawn unlocks, running out to h8.
One second-rank pawn starts with no defender at all: h2.
The setup belongs to the ThroneScout family; read right to left it becomes position 231.
The engine's main line opens with f4.
Morozov Balance Index: 83 of 100 — class A — most balanced. Engine evaluation of the starting position: +16 centipawns for White (depth 43, 400 000 000 nodes).
Explore position #626Provenance
Mined from the project's engine self-play games.
Pack 013 · SP-626
Similar puzzles
In your browser or in the Android app. Nothing to install · Free, no ads