Modular U-Bahn
(Published on 12. July 2025, 00:00 by cyddrdrd)
Thank you Maddie and MonsieurTRISTE for testing it!
Rules
- Normal sudoku: Fill the grid with digits 1-9, so that no digit repeats in the same row, column, or 3×3 box.
- U-Bahn: Draw a totally connected loop network through the centers of some cells in the 9×9 area. The network may branch or turn, but may not have any dead ends. Clues outside the grid indicate how many times the corresponding line shape (cross, branch, straight line, or turn) appears in that row/column, regardless of rotation.
- Interaction: Assign line shapes to digits (irrespective of rotation) as follows:
- Corner = 1
- Straight line = 2
- Branch = 3
- Cross = 4
Penpa+
SudokuPad
Solution code: For each column except the last, from left to right, the number of lines leading right from that column; followed by row 3. (17 digits in total)
Comments
on 18. July 2025, 03:04 by yttrio
Incredible hybrid!
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rdrd: Thanks! Glad you like it.
on 13. July 2025, 20:36 by lhy2407
Very wonderful puzzle! Thanks!
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rdrd: I appreciate it!
on 13. July 2025, 13:11 by zuzanina
很好玩，谢谢！
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rdrd: 很荣幸～
on 13. July 2025, 03:41 by dragoond
Exceptional puzzle! Curious about the setting strategy for U-bahns. Two thoughts: Would a 6x6 snack be interesting possible? What about connecting to juggler's tessellation grid?
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rdrd: good idea! I might try those later. Thanks!
on 12. July 2025, 23:42 by MaizeGator
Awesome! I will admit that I was skeptical to see such an ambitious ruleset by a first-time poster, but I was thoroughly impressed by the variety of logic throughout and an extremely nice finish. Respect!
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rdrd: Thanks, I am really flattered :)
on 12. July 2025, 20:01 by Piatato
Lovely!
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rdrd: Thanks!
on 12. July 2025, 19:22 by AutoNick
Amazing, thanks for sharing!
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rdrd: Thank you!
on 12. July 2025, 19:16 by wooferzfg
Fun puzzle, thanks!
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rdrd: I appreciate it!
on 12. July 2025, 15:48 by Bellsita
Very fun puzzle! Thanks!
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rdrd: Glad you enjoyed!
on 12. July 2025, 14:35 by marcmees
Impressive first puzzle. Was fun to solve and luckily more approachable than the ones of setters who inspired this puzzle. :-)
Thanks
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rdrd: Thanks and glad you had fun!
on 12. July 2025, 14:04 by Agent
Cool idea and very smooth solve! I enjoyed it a lot.
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rdrd: Thank you! Glad to hear that!
on 12. July 2025, 12:55 by Playmaker6174
@SparkNights: The network doesn't have to pass through every cell in the grid, just only some of them.
on 12. July 2025, 12:51 by SparkNights
How does 4s and 8s in edge cells work?
on 12. July 2025, 11:21 by cyddrdrd
Sudoku tag added :)
on 12. July 2025, 11:15 by Playmaker6174
Wow, lots of beautiful interactions between two genres, super impressive achievement for the first puzzle! (you should add 'sudoku' tag into this as well)
At first it didn't seem like it'd actually resolve at the end, but then I was proven very wrong there x)
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rdrd: Thanks for your suggestion! Tag added :)
on 12. July 2025, 10:09 by KNT
impressive and enjoyable debut puzzle! Thanks a lot!
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rdrd: Thanks KNT! I appreciate it!
on 12. July 2025, 09:39 by Myxo
Awesome first puzzle! Looking forward to more :)
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rdrd: Glad you enjoyed it! Looking forward to more puzzles from you too x)
on 12. July 2025, 05:44 by h5663454
下次整个解构
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rdrd: 我努力
on 12. July 2025, 01:54 by Christounet
Cool :)
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rdrd: Thanks!
on 12. July 2025, 00:05 by maddie
Very nice! Looking forward to your next puzzle!
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rdrd: Thank you and glad you like it!
