Su Doku is a number grid consisting of 9 large squares each divided into 9 smaller squares. Between 3 and 4 numbers are already provided in each of the smaller squares. The point is to fill the grid so that every column, every row and every 3x3 box contains the digits 1 to 9.
This book contains over 100 unpublished puzzles graded easy, medium and hard. Since The Times started to publish Su Doku they have received an enormous number of enquires about the puzzle and a puzzle book.