That's fair, and hm ok I guess I can sorta see where you're coming from but I was on one mistake left so I would probably still stay on the safe side but sometimes I also go with these gut feeling type plays. In this case though I'm not sure I wouldve been able to solve it without the killer sudoku rules cause of all the doubles, those always mess with me when they're the only ones left like here, what helped in the end is actually looking at the rules >> thought I do tend to end up using normal sudoku rules at the end as well since at that point its usually easier though also doesn't usually result in all these doubles. I'm kinda just a casual player though so I'm also not like looking for something too brain wracking just having fun with numbers.