Unexpected Fun: Solving Sudoku Killer in Winter

Recently I had trouble to keep up the weekly running frequency due to the cold. Last 2 weeks temperatures dropped close to freezing point and on top of that it started snowing for almost a week. Luckily I still had some days off so I didn’t have to endure snow triggered traffic jams. Luckily our paper had a puzzle special page with something they called the Sudoku Killer. This is a normal Sudoku but a lot fewer numbers pre filled and instead grouped squares for which the total sum of the numbers to fill is given. As can be seen in the picture very few bold pre filled numbers are given indeed. As a result it takes quite a bit more time to complete one such Sudoku. Time I had because I had days off and didn’t manage to convince myself to go out running. I liked solving these but would not spend the hours on a regular weekday evening after work myself. I would probably save them for later and then end up with a Sudoku puzzle backlog cluttering my library. And I would have even less time to go running and to read all the books that are also cluttering the library.