Each line obeys exactly two of the following rules.
Entropic Lines: Along an entropic line, any three consecutive cells must contain a low digit {1,2,3}, a medium digit {4,5,6}, and a high digit {7,8,9}.
German Whispers: Along a German Whispers line, consecutive digits must differ by at least 5.
Region Sum Lines: Along a region sum line, digits must have the same sum in each 3x3 box through which the line passes.
Renban: A renban line must contain a non-repeating group of consecutive digits, which may appear in any order.
f-puzzles: https://f-puzzles.com/?id=2oyzvace
CTC: https://tinyurl.com/2p8r4uyb
Solution code: Row 4 + Column 8 (18 digits)
on 20. October 2022, 11:30 by Chilly
Great puzzle. Very neat.
on 14. October 2022, 18:45 by lerroyy
Very nice puzzle! thanks
on 14. October 2022, 16:34 by Playmaker6174
This puzzle was extremely enjoyable to me, lots of neat deductions and some unexpected moments while deducing each line properties ;)