Normal sudoku rules apply.
Quadruples: Digits in a circle must appear at least once in the four cells the circle touches.
159: Each digit in column 1 indicates the position of the 1 in the same row (for instance, if row 3 column 1 is a 2, row 3 column 2 is a 1). The same is true of columns 5 and 9 for the digits 5 and 9, respectively.
Solve online:
Solution code: Row 7, followed by column 3 (18 digits, no spaces).
on 18. December 2023, 00:02 by ScienceNerd2240
solution code doesn't seem to be working for me currently, I've tried multiple times carefully entering the digits
edit: nvm figured it out. the ctc app didn't check for the proper digits around the quads
on 27. September 2023, 07:13 by cascadeshiker
Very nice. Very enjoyable. I'll be looking out for more 159 puzzles.
on 12. August 2022, 09:28 by Crusader175
Beautiful puzzle!
on 12. August 2022, 05:13 by SHERAX
Fairly Easy But Highly Original
on 12. August 2022, 05:13 by SHERAX
Fairly Easy But Highly Original
on 30. June 2022, 09:03 by 99jau99
I really enjoyed solving this puzzle. Congratulations to both of you!
on 30. June 2022, 07:20 by cristophermoore
Delightful! Congratulations to you both.
on 28. June 2022, 17:35 by Christounet
That's my boy !!
on 28. June 2022, 13:22 by Chilly
Lovely puzzle - watch out grkles, looks like grkles junior is going to take over!
on 28. June 2022, 03:17 by Vebby
Very nice! Flowed beautifully.
on 27. June 2022, 23:18 by Chelo
Very nice puzzle, many thanks to you and to your son for setting and sharing!..
on 27. June 2022, 22:06 by Elliott810
Beautiful puzzle! One can literally see how this puzzle was set. Shout-out to father and son:)
on 27. June 2022, 20:07 by Playmaker6174
Lovely puzzle! Nice to see the unexpected teamwork there :)
on 27. June 2022, 16:31 by Niverio
Very nice! I cannot wait for Grkles Jr. to come up with mind blowing ideas soon :)