Fill in the numbers in the sudoku grid in this sudoku game. Use the blue numbers to fill in the definite number, or switch to red, which is pencil mode. This allows you to note down some possible numbers to fill in. But watch out, in this sudoku game you can only fill in a maximum of 4 pencilled numbers. Can you solve this sudoku puzzle? Numbers may only occur once in every row, column, and block of 9 squares. Good luck