From 2008 until the beginning of 2013 I have been writing sudoku variants for a sudoku magazine on a monthly basis. One of the variants was the Irregular Twin (or: Twin Chaos). It was always my favorite variant of the set. I really enjoyed searching grid lay-outs that could be combined. The most beautiful one that I have ever made contained only eight given digits, which is, of course, the absolute minimum. It was too hard for the magazine, so I published it here in the portal. It has been a while since I have written an Irregular Twin, and since I like it so much, I reserved this type to be the 100th variant in my SVS. It has 10 given digits, but with a very nice arrangement. Enjoy it!
Irregular Twin
Solve online in Penpa+ (thx bbutrosghali!)
Place the digits from 1 to 9 in every row, column and bold outlined irregular area of both grids. Both grids have the same solution.
Solution code: Row 5, followed by row 9.
on 27. November 2022, 12:41 by Piatato
Amazing! Thanks for taking the time to find this beauty for us. :-D
on 14. July 2022, 11:47 by Richard
Added link and tag for online solving. Thx bbutrosghali!
on 31. March 2021, 18:23 by bbutrosghali
Penpa implementation:
https://git.io/JY2rw
on 31. March 2021, 15:18 by Tintenklexs
Wow, consider me blown away. This was SUCH a treat. It was my first time trying my hand at this type of Sudoku and what a joy it was. It felt like a wonderful, harmonious movement of my mind, swinging back and forth between the two Sudokus, slowly making sense of it. I feel so refreshed right now.
Thank you so much, Richard!
on 26. November 2020, 22:33 by SirWoezel
Finally! What a fantastic puzzle. But I surely hope I’ll never have to restart the same puzzle again as often as I had to restart this one.
on 1. June 2020, 07:03 by Phistomefel
@Richard: Thanks a lot for your answer! I have to admit that I hoped there would be a technique for setting such a beautiful pattern of digits, but the fine tuning of a puzzle always takes its time.
on 1. June 2020, 06:41 by Richard
@Phistomefel: Most important is a combination of grids that don't conflict with the Law of Leftovers. After that, placing givens is a matter of T&E to find a nice arrangement that works. This took ages, as I remember it right. (It's already five years ago...)
on 31. May 2020, 14:48 by Phistomefel
Very nice puzzle! The interplay of the geometry in the two grids is amazing and very enjoyable. If I may ask a question about the construction process, I would love to know how you came up with this beautiful arrangement of the given digits.
on 28. September 2017, 17:43 by JonaS2010
Fantastic puzzle! Now I am halfway through with all puzzles so far, and look forward to the next 100 :)
on 18. November 2016, 10:42 by ohm0123
Cool. Cool. Cool.
on 27. September 2016, 22:41 by Danielle
Uiii, sehr schön!
on 30. October 2015, 16:43 by HaSe
wunderschön
on 28. October 2015, 15:27 by Rollo
Ganz toll!!!
on 28. October 2015, 06:13 by Richard
Label change
on 27. October 2015, 17:18 by AnnaTh
Another masterpiece! Thank you! Happy 100!
on 27. October 2015, 13:17 by flaemmchen
Vielen Dank Richard für die vielen schönen Sudokus dieser Reihe! Und auch ich freue mich schon auf die nächsten 100 :-))
on 27. October 2015, 12:31 by marcmees
thanks Richard.
on 27. October 2015, 11:52 by pin7guin
Vielen Dank, Richard! Und ich schließe mich meinen Vorrednern an. :-)
on 27. October 2015, 10:48 by Senior
Excellent No. 100 - congratulations and thank you, Richard!
on 27. October 2015, 08:17 by ibag
Very nice No. 100. I'm looking forward to the next 100 Sudokus!
on 27. October 2015, 07:31 by rcg
Congratulations Richard with your 100th suduko variant. I look forward to the next 100.