This is not a collection of sudoku puzzles, but a classroom to teach you the methods and rules to solve sudoku puzzles. You can learn the following rules:

A1,A2,A3,A4,A5,A6,A7
B1
C1,C2,C3
D1,D2,D3
E1,E2
H1
X1
Y1
Box2Line
Line2Box
Na-kedPa-irBox
Na-kedPa-irLine
HiddenPairBox
HiddenPairLine
Chain

More rules are being developed and will be introduced later. Besides the rules, this app also teaches you how to use candidate list and depth-first-search to solve difficult puzzles.

Other features of the app:
- 3 levels * 100 sudoku puzzles are included
- each puzzle are labeled with difficulty, whether candidate list necessary to solve it, whether depth search necessary to solve it
- when help is pressed and a step is given, question button can be used to understand which how this step is calculated
- customize button can be used to enter difficult puzzles found elsewhere, this app will help you learn how to solve it
- when new customized puzzle is entered, you can use this app to evaluate

Become sudoku expert with this app!