The Guardian has published Sudoku 7403, a demanding expert-level puzzle for fans of the classic number game.
Classic Sudoku rules
As with all standard Sudoku grids, the aim is to fill a 9x9 board so that each row, column and 3x3 box contains the digits 1 to 9 exactly once. Sudoku 7403 is rated expert, meaning solvers will need advanced strategies to complete it.
