Sudoku

How to use this Sudoku grid:

First click on the right side bar of the grid to select a digit. Then click on the square where you want to place the selected digit (or to remove the selected digit).

Pencil mark allows multiple possibilities to be placed in the squares. However if only one digit is in a square, that digit will be automatically converted to a regular entry. Single digit guess can be made and distinguished from the regular entries with the background hightlight option.