The Box checkmate

White's move 4 is not correct, there is a shorter way.

how?

Qb3#

Also, on move 3. Kc3 and 3. Kc4 lead to the same mate. But that is nothing compared to move 4, when mate-in-1 is called "incorrect".

Please check your future puzzles with an engine.

A box mate should be a rook and a king trying to checkmate their opponent. Not using a queen.

Box, boxing, rectangle: different words for a method to mate with king and queen (basically contain the enemy king in a square (box) and make that square smaller and smaller till the enemy king is at the edge of the board).

Killer box: mating pattern with a queen and a rook (queen and rook make a box of 3x3 squares. The queen defends the rook. The enemy king is trapped on the rook file).