Comfortable Sudoku

Features Comfortable Sudoku

Sudoku is a logic-based,number-placement puzzle.
The objective is to fill empty grid with digits so that each column, each row, and each of the nine 3×3 block that compose the grid contains all of the digits from 1 to 9.
Comfortable Sudoku features:
★Press and hold a grid, you can enter a number directly.

☆10 different levels of difficulty
☆Three input modes
☆Undo / Redo
☆Hint mode