Sudoku -- official Nikoli

Even first-timers can have fun! Carefully selected 200 good Sudoku puzzles from Nikoli, the home of Sudoku!
Includes how-to guides and explanatory videos. This is a Sudoku application that can be enjoyed by everyone from very beginners to experts.
# From very beginner to advanced! Questions listed by difficulty level!
Questions are listed according to difficulty levels: super beginner, beginner, intermediate, and advanced, so everyone from beginners to experts can enjoy the puzzles.
# Original problems by Nikoli, the puzzle group that created Sudoku!
The puzzles are created by Nikoli, the puzzle group that created Sudoku, which is loved in 100 countries around the world, and are therefore full of good problems. Each puzzle has only one answer (there is no alternative solution). The exhilaration when you solve a puzzle is exceptional because you can always arrive at the correct answer if you solve it logically and not by guessing.
# Rules, solving instructions are included, so even first-timers don't have to worry!
Did you know that there are 6 ways to solve a Sudoku? Nikoli's Sudoku puzzles can be solved in any of these six ways, and you can enjoy solving them while learning how to solve Sudoku puzzles, with links to explanations.
* ""SUDOKU"" is a registered trademark of Nikoli, Inc.
* This application is produced under a formal license agreement from Nikoli, Inc.