This Sudoku type has several variants. You can find the procedure under Explanation.

       Variant 1                                                                                                                                         Variant 2   

Variant 1

Download The Explanation.

Download the Puzzels (including solution):

1. Puzzel *
2. Puzzel **
3. Puzzel ***  

Variant 2

Download The Explanation.

Download the Puzzels (including solution):

1. Puzzel *
2. Puzzel **
3. Puzzel ***