Empty Boxes: All About Disjoint Sets in this Sudoku

[@DjembeMatt]

Hi, Meggen033 here. Great solve. The empty boxes were indeed the bottom right 4 boxes. I tried to set the puzzle with all those boxes empty, but couldn't quite get it and had to squeek that whisper line into box 5 for it to solve. One trick that may be helpfull that I use for solving/setting disjoints is to highlight sets one at time to see what's left over to pencil mark those cells. I only highlight one set at a time so I don't get overwhelmed by having to scan colors as well as numbers. Again, great solve and thanks for highlighting this and all the other great puzzles out there! Cheers and God Bless 😎

[@livedandletdie]

It was quite a fun puzzle to solve. Disjoint is such a fun constraint. It really gets your noggin going.

[@Paolo_De_Leva]

Well done. I agree that colouring disjoint sets might be overwhelming in this case, and pencilmarking them one at a time is a good advice.

[@SudokuSleuth]

Thank you for stopping by, the kind comments, and of course the puzzle! Clever idea about how to solve the disjoint sets, must try it in the next one I try.

[@jonbrowne]

18:31 to solve with pencil mark check ON. Great puzzle which has some tricky deductions to start and then the disjoint is a little bit laborious.

[@victorfinberg8595]

one important rule that is not mentioned and is NOT automatic is "no repeats in cages" pretty sure it is required

[@anaayoung9142]

The disjoint rule set is usually very hard but on this puzzle was super cool! Well done! 😀

[@IAlreadyHaveAKey]

At around 26 minutes when you pencil marked 8s into box 8, you could have used the fact that in one of the boxes you need an 8 in the middle left position, and at that point box 8 is the only one where that's possible. Might have sped things up a bit, but I think disjoint sets are just in general difficult to scan for

[@SudokuSleuth]

Nice spot, and yes they're very awkward to spot sometimes!

[@chrisbrogan3307]

Very enjoyable puzzle

[@SudokuSleuth]

It really is!

[@RilianSharp]

my time 19:05 :)

[@thelostking953]

The ruleset does not tell, that a cage need to be made with individual digits, therefore the assumption of the 7-cage at the start might be wring, as it could 1-5-1 or 2-3-2 as well. Or am I wrong?

[@damdamdamdumdidum]

You're right, the ruleset doesn't tell that, but I think the setter just forgot to mention it. I solved it with the normal Killer Sudoku rules in mind and it was correct.

[@phuybrechts6875]

The 7 in box 4 could help in box 3

[@phuybrechts6875]

You got lucky! You pencil 249 instead of 349 in box 6 ! And then remove the 2 😊

[@SudokuSleuth]

😁, that was lucky!

[@andreiandries470]

There's no mention of the rule "digits can't repeat in cages", so can't that 7 be made of 1+1+5 or 2+2+3?

[@SudokuSleuth]

Good call! I don't know if it's an oversight by the setter or not. Looking at it now!