The sudoku in this collection of 156 puzzles vary in difficulty from fairly easy in the beginning to really quite awkward by the end. They are divided into four levels of difficulty - easiest, easier, harder, and difficult. Solve Sudoku online at www.puzzles.kiwi.nz Try vaki puzzles at www.vakipuzzles.com Or try our big book of mixed puzzles - MindSport puzzles vol 2.