Sudoku (数独 sūdoku, digit-single) (/suːˈdoʊkuː/, /-ˈdɒk-/, /sə-/, originally
called Number Place) is a logic-based, combinatorial number-placement puzzle.
The objective is to fill a 9×9 grid with digits so that each column, each row,
and each of the nine 3×3 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.