Sudoku Zen: Logic Number Brain app for iPhone and iPad

A classic digital logic game from the Sudoku zen:puzzle game， From the simplest four-grid sudoku to the classic nine-grid sudoku, the difficulty gradually meets your logic challenges!
Features:
• The classic Sudoku design
• Use the pencil to make notes right on the puzzle
• Highlight duplicates to help you solve the puzzle
• Challenge yourself by limiting yourself to three mistakes
• Use hints to help you find your way through difficult puzzles
• Four perfectly crafted difficulty levels: Easy, Medium, Hard, and Expert.
• Highlight duplicates to avoid repeating numbers in a row, column, and block
• Pencil mode: Use the pencil mode to make notes on each cell, which automatically update as you play the game
• Statistics: See your best times and streaks for every difficulty level
• Autosave: Your puzzles save as you go, so you can come back anytime
• Hints: Hints can guide you through the puzzle when you are stuc