Each row, column and 3x3 square must contain exactly one of each digit, 1-9.
Please watch part two of "How to Solve a Sudoku" on your right.
(Recommended).
On the left, you may watch yesterday's guest puzzle (acfy)
solve itself by clicking Hint repeatedly. Thus you can confirm that
there is a valid solution path for yesterday's guest puzzle. However,
the path shown is not what a player would normally use, so this
demonstration is not recommended as a tutorial.
