Sudoku is a logic number-game invented by the Swiss mathematician Euler in the 18th century.

The rules of sudoku is simple: fill in numbers 1-9 in the nine 3X3-panes, and keep 9 numbers in the panel of every lateral and vertical direction not repreated

There are some features and assisting tools to help the player to play easier.

5 levels of difficulties and 400 selected sudokus.
automatic pencil
Backward function
Input Suggestion
Sideline reminder
No electronic dormancy or black screen

Screenshots: