By clicking on the box you select it and then you can enter a digit.
Digits can be entered by clicking on the pencil icon in the lower right
corner of each cell. It then displays „on-screen keyboard“, where clicking
on a digit you will ensure its completion within thec ell.
You can write down numbers which can be considered for the cell. Entering
options – click on the rectangle below the number for the „on-screen
For a hint you can click on the question mark next to „on-screen
Sudoku solving status is continuously saved in your browser. If you are
logged in, you can save the state of solving also in your user account and then
upload to another computer.
Press the Check correctness option to verify that your solution does not
contain any contradiction to the rules of Sudoku.