The Game of Sudoku.

Wikipedia, the free encyclopedia states the name Sudoku is the Japanese abbreviation of a longer phrase, "suji wa dokushin ni kagiru," meaning "the digits must remain single"

The goal is to place one number in each of the 81 cells, so that each column, row, and 3 by 3 group contains the numbers 1 to 9 exactly once. Each number in the solution therefore occurs only once in each of three "directions" or "scopes", hence the "single numbers" implied by the puzzle's name.

The game board is made up of nine groups of cells organized as 3 columns of groups with 3 rows of groups in each column. Each group has 9 cells organized as 3 columns of cells with 3 rows of cells in each column. This results in a game board with 9 columns of cells with 9 rows of cells in each column.