Additionally, a variant of Sandwich sudoku rules apply:
1, 5, and 9 act as 'bread' and divide the row or column into two outside groups and two inner ('meat') groups.
The clues along the edges along are the difference in the sums of the 'meat' groups.
For instance, a row that was '123456789' would have 'meat' of 2+3+4=9 and 6+7+8=21, so the clue for that row would be 12 (21-9).
You can try it on Penpa.
Solution code: Rows 7 and 9, spaces between numbers and a comma-space between the rows
on 11. August 2020, 22:35 by pjz
Fixed puzzle, updated Penpa link
on 11. August 2020, 21:27 by pjz
Updated rules/instructions
on 10. August 2020, 23:53 by marcmees
this puzzle was fun, certainly deserves more solvers. maybe the ruleset could be explained better. Mentioning the outside regions may confuse as the hints outside the grid only indicate the difference of the sums of the inner regions, squeezed in between 1/5/9 (whatever their order of appearance). Thanks for the fun puzzle
on 7. August 2020, 08:03 by jackisaacbryan
A great solve! It didn't topple until right at the end, which made every minute worth while.
on 7. August 2020, 07:32 by pjz
added the penpa link