Sudoku
(also known as "
Number Place
") is a logic-based, combinatorial number-placement puzzle. The objective is to fill a
9x9
grid with digits so that each column, each row, and each of the nine
3x3
subgrids that compose the grid (also called "boxes", "blocks", or "regions") contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution.
Outside Sudoku
is a variation of the standard sudoku. Some digits are given outside the grid. These digits must appear in the first three cells in the corresponding direction.