Irrwisch Sudoku: X-Sums
(Published on 1. June 2023, 01:41 by Gliperal)
Normal sudoku rules apply.
Clues outside the grid are x-sums clues, which represent the sum of the first X digits (where X is the digit in the first cell) in that direction.
All clues are encrypted: Every digit within a clue has been replaced with either a ? or a letter. The letters A, B, and C are each an irrwisch, which represent a different digit every time they appear. Two-digit clues may not start with a 0, but one-digit clues may.
Example:
Solution code: Row 5, Column 5
Comments
on 28. June 2025, 16:30 by skuntsel
This is just sublime. People like Gliperal are way ahead many others, by miles. I still don’t believe how this all resolves, it’s just on the very brink of being resolved at all: not once, not twice, seems like not even 10 times, literally. You’re always questioning yourself if you’ve found the wrong way to crack the puzzle open, because you find it hard to believe that it all can resolve just like that, eliminating many variant one after the other so effortlessly, clean, and just one tiny step to being resolved, one worth of value off - and it’s not manageable at all. And then you just remember that it’s Gliperal and that this must have been chosen on purpose, and that’s not a coincidence, hence you’re on a right path.
The interaction between box 1 and column 9 is just impeccable and extraordinary. It is really hard to unravel the mystery behind it, let alone count it as approachable, although you understand everything, feel the reasoning behind, and have made the proper break-in, having solved quite a few of the puzzles on the harder spectrum. Even at the very end it was truly remarkable as you’ll have to spot an X wing to complete the last clue, not directly of course, via eliminating all but one digit in a pointing cell, and if that wasn’t enough for you, you’ll have to use that very cryptic last clue and you of course won’t ever be surprised that that one was hardly even a restriction at all throughout. And voila, you’ve successfully completed the ‘approachable’ puzzle!
I don’t imagine at all how you can even come up with such a concept, not only implement it so masterfully. It was a true pleasure to solve this stunning puzzle! Thank you, Gliperal, it was very enjoyable!
on 1. August 2023, 00:47 by shteev
How can a one-digit clue start with a 0?!
on 18. July 2023, 00:47 by samuel1997
This puzzle is amazing! I hope this could be featured on CTC!
on 21. June 2023, 01:29 by Silverstep
Much more approachable than the sandwich one. This should be on CtC at some point.
on 5. June 2023, 20:41 by madhupt
A great puzzle by Gliperal. Looked very difficult at first but after the quick initial breakthrough, I had to backtrack several times as kept on forgetting the various used up values. In the latter half, sorting C9 and C3 took some effort but fell through very beautifully when I kept on the logical solve path making small deductions. Thanks a lot for sharing.
on 2. June 2023, 21:22 by KNT
really impressive construction
on 2. June 2023, 18:51 by Elliptical
Sublime! I think that's a good candidate for a CTC video.
on 1. June 2023, 21:04 by Bankey
Beautiful puzzle. But requires constant and careful focus and the ability to memorise what can go where, particularly due to lack of any pencilmarking provision outside the grid. On the whole, an enjoyable ride. Thanks, @ Gliperal:)
on 1. June 2023, 20:58 by henrypijames
One digit clue may start with (and therefore be) 0? Since when is 0 a valid x-sum?
@henrypijames Whoops, that's a holdover from the sandwich puzzle rules.
on 1. June 2023, 16:26 by Snookerfan
Brilliant puzzle! Thank you
on 1. June 2023, 10:56 by Niverio
Absolutely fascinating that you can come up with these very unique ideas :) Lovely!
on 1. June 2023, 10:18 by Playmaker6174
Very lovely puzzle! Though getting trickier towards later half, the solve remained interesting and entertaining to the end :)
on 1. June 2023, 03:09 by Myxo
Awesome puzzle!
on 1. June 2023, 01:45 by cornish-john
Very enjoyable solve, thanks!
