Its Just Sudoku
Not availableFill in the the grid so that every row, column, and 3 x 3 box contains the numbers 1 - 9.
That's it.
(Come on, it's Sudoku, we all know how to play this)
For some reason the description to be at least 400 characters, but someone once quite rightfully pointed out that if you can't describe something in a single sentence, then you're not an expert on the subject. I honestly can't remember who said it, probably Einstein.