Activity Workshop
 

Sudoku - Puzzle 4

This fourth puzzle is not quite as straightforward as the first three, and is rated medium. Some more thinking might be required for this one.

As before, you can resize your browser window to make the puzzle bigger or smaller as you want. To fill in a number that you definitely know, use your mouse to left-click on the square and select the number. If you're not sure but want to mark a possibility (for example, the 2 can either be here or here), then right-click on the square instead and select the number. This possibility will be written smaller and grey in the corner of the square, like a pencil mark to remind you.

The code running here is from the ActivityWorkshop, and the numbers were generated using the free (GPL'd) software Sudoku Sensei. This example is coded as N2x01-057 which means a single level 2 rule is needed to solve it, and it starts with 57 empty squares. It's this level 2 rule which bumps the complexity up to medium.