Unique Japanese Sum Sudoku
(Published on 28. July 2023, 05:34 by tesseralis)
I came up with the idea of this puzzle during a red-eye flight, and worked on it on the plane, at the airport cafe, and in the hotel lobby waiting for check-in. It's frankly a miracle that this resolves, and I hope you all find it as fun to solve as I did to create it!
Rules
Normal sudoku rules apply. Digits joined by a white dot are consecutive.
Japanese sums: Shade some cells in the grid such that the clues outside the grid indicate the sums of the contiguous runs of shaded cells found in that row or column. Multiple runs in the same row or column must be separated by at least one unshaded cell.
Each caged cell represents a unique positive number. A question mark can represent any positive number.
Solution code: Column 1
Comments
on 8. October 2023, 18:25 by Muhammad
What a puzzle! this is brutal, it took me 3 hours to solve it.
on 23. September 2023, 03:55 by konklone
One of my all time favorites, for sure. Wow. I got real stuck at the hard midsolve step mentioned a couple times below, and came very close to giving up, but coming back to it after a few days' break helped me see new things and keep it moving.
It's not only amazing that it resolves, but that there are so many interesting late game deductions too. I don't know how you lined all this up. Amazing work, tesseralis!
--
Thank you for persevering and playing through the puzzle!
As for how I managed to make it line up: a little bit of grit and a lot of luck :)
on 14. September 2023, 10:12 by marcmees
incredibly nice. thanks
on 8. September 2023, 18:10 by ddx01
This puzzle is insanely good! I also find the solution path to be very clear. I always had things to think about in order to make a progress, and never felt completely stuck. Which was quite surprising for me, as I guess I expected it to be more difficult than it actually is.
on 6. September 2023, 18:27 by OGRussHood
This puzzle is mad.
on 15. August 2023, 13:10 by Xendari
Insane puzzle!! Once I started thinking about the right way to approach it, it was really smooth. Thank you for sharing :)
on 11. August 2023, 20:47 by Agent
Very impressive construction! Feels like there's barely enough information at every stage of the puzzle.
--
thanks Agent! always glad to see your solves ^_^ ~tess
on 8. August 2023, 15:23 by Lizzy01
It is indeed a miracle that this solves!
Very hard for sure, it took me over 3 hours in total, across multiple days. I almost gave up halfway when I got stuck at exactly the same step as Samuel describes in his hidden comment, but when I came back to it a few days later I finally spotted the right place to look, and managed to finish it!
Very nice puzzle, when you're not staring at it for an hour getting nothing further because you've done every possible calculation except the needed one which turns out to be the first one you looked at just using maximums instead of minimums....:/
These have nothing to do with this puzzle, but just the general minimalist 'unique clues' idea slightly reminds me of these two puzzles:
https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000AN6
https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=0009JY
If you like this one, you might like to check those out too. (They aren't as hard as this one, especially the second one is clearly easier.)
--
Thanks! I've done the watchtower puzzle but I'll check out the chaos construction when I have time. :)
on 8. August 2023, 11:25 by samuel1997
This is the most interesting and brutal puzzle I have ever solved! Struggle for 3 days and finally get there!
--
Congratulations! Thank you for persevering and solving this. <3 ~tess
on 5. August 2023, 13:23 by juhish
I've had this open on my laptop since Wednesday. I finally solved it. It's Saturday. I guess I will rate this very hard. And 100%.
--
thank you for persevering! ~tess
on 4. August 2023, 16:03 by BHUNTER47
This is one of the best puzzles I have ever solved. Took me multiple hours but getting the solution correct was worth all of that time.
--
congratulations! glad you enjoyed it :D ~tess
on 4. August 2023, 06:22 by bansalsaab
Wow. I gave up many times on this one but finally done.
on 31. July 2023, 11:42 by tesseralis
Actually fixed Sudokupad link
on 31. July 2023, 11:38 by tesseralis
Fixed the sudokupad link.
on 30. July 2023, 20:47 by tesseralis
Add SudokuPad link
on 30. July 2023, 19:51 by peacherwu2
Rule clarification? Is it ok to have an entire row or column of shaded cells? "Multiple runs in the same row or column must be separated by at least one unshaded cell."
--
yup! that's only one run so it doesn't need to be separated by anything ~tess
--
Well in that case, I think that is a tautology and only confusing as many Japanese sums wouldn't allow it.
--
how would you word it then?
--
That is not needed, IMO.
on 30. July 2023, 14:06 by dennischen
What the heck, this is miraculous. The midgame was so subtle and I thought, "there must be some really obvious step I am missing" and yet there wasn't.
--
it's magic isn't it? ~tess
on 30. July 2023, 00:44 by Fool on Hill
Astonishing construction. Once the logic is found it is clean and beautiful. Finding out what is going on - that is another matter. A brilliant and very hard puzzle
on 29. July 2023, 00:37 by JayForty
Beautiful construction! Loved the shading and sums logic. Thanks!
--
thanks for the kind words! ~tess
on 28. July 2023, 23:26 by Myxo
Absolutely incredible puzzle! Loved it!
on 28. July 2023, 08:25 by RJBlarmo
Very nice puzzle! Agreed that there are some tricky bits in the midsolve but nothing unfair and it's impressive that the grid resolves with minimal information.
--
heh, I'm as impressed as all y'all ~tess
on 28. July 2023, 07:36 by henrypijames
Yeah, that midgame step is a killer!
on 28. July 2023, 07:18 by Christounet
Impressive construction ! Enjoyed testing this very much. A lot of interesting things in the opening. Very original shading. Some harder deductions in the midsolve, but still fair, and it gets rewarded with very flowy ending. Thanks :)
