Sudoku Rules

Classic Sudoku is a popular puzzle game, where you have to enter numbers (1-9) into 9x9 grid. Several numbers are given (clues). There are million of combinations but "good" Sudoku have only one solution.

1) 9x9 grid,
2) column,
3) Row
4) 3x3 Region
5) Given number (clue)
6) Empty cell (you have to enter numbers from 1 to 9)

The only simple rule is that number can not be repeated in same row, column or 3x3 region.

Real Sudoku have only one result. Standard Sudoku (with unique result) can be solved with pure logical thinking (without guessing).

Row rule:

Column rule:

Region rule