Rules:
Normal sudoku rules apply. In addition, the nine Tube lines have the following rules:
(N.B: the purple and grey lines run parallel from r4c3 to r2c1. The pale green and black lines run parallel from r7c7 to r6c7. In ALL CASES, digits may repeat freely on a line if permitted by other rules.)
Links to online solving tools:
Solution code: Row 3
on 9. July 2026, 14:30 by sockerbecca
I was surprised to see this hasn't gotten more solves, I thought it was very nice! I love theme sudokus and the lines interacted well!
It's a bit hard to distinguish the different colours because they are so similar in hue, but I understand it's because of the theme and I just drew over them with the pen tool as needed. (You could have slapped a function onto the brown unused line as it fits within the same ruleset as another colour, but I don't think it would have affected the actual solve so also makes sense to just leave it out.)
All in all I really liked this!
on 25. January 2023, 01:54 by Mr.CHEN
I want to correct it. The light-blue line (Victoria line) should be "anti-whisper" rather than "anti-renban"
Whoops - thank you, I've updated the rules description above! ~Mojo872
on 23. December 2022, 17:31 by ViKingPrime
Took me longer than I care to admit (given a few careless errors), enjoyable logic though and a clever theme. Well done!
Thank you! This one was a case of "theme over function", as there were a couple of steps I thought were a bit finicky, but wasn't willing to compromise on the design :p ~ Mojo872
on 23. December 2022, 09:44 by dodomos
London?
Yes! I thought it went without saying but I now realise that's very UK-centric of me - editing to clarify :)