Sudoku Classic

A 9x9 grid fills the screen in Sudoku Classic. Nine smaller 3x3 boxes divide the board, and every empty cell waits for a digit from 1 through 9. Five difficulty options change the number of clues placed at the beginning. Easy leaves more given numbers on the grid. Expert and mad leave far fewer, which changes how much of the board is already filled before the first move.

How to play?

Place digits into the empty cells and check each choice against the surrounding row, column, and 3x3 box. A number may appear only once within each of those spaces. Use the given digits as clues when narrowing down the remaining spots. Notes are available for marking possible values inside a cell. Automatic error checking can be switched on or off in the settings. Time isn't limited, and the board stays available until all 81 cells hold valid numbers. A square with more filled positions is a useful place to begin. Guess a number and review it later, or leave auto-check active to flag a wrong move right away.