You are playing the puzzle that was published on Monday, 31st of May 2021.
This puzzle is rated (very difficult).
Caution: leaving this page without saving will erase the current progress.
Hover the mouse over the grid. Type the number you want to enter in the cell. Press the space bar to toggle between entering final numbers or pencil marks.
Point to the cell you want to change and left-click to display a selector.
Using the selector you can add or change the value, add or remove pencil marks or change the color of the cell.
This is still a work in progress. If you have suggestions for improvement or if you find any problems, please let me know using the contact form.
Thank you for any feedback!