A Sudoku is a puzzle involving a 9x9 grid into which the ... These equivalent sets can be very useful for hard Sudokus where all the usual methods aren't getting anywhere,' she added. ' ...

At its core, Sudoku is a logic-based puzzle that challenges you to fill a 9×9 grid with numbers in such a way that each column, row, and 3×3 subgrid contains all the digits from 1 to 9, without ...