Yin Yang Sandwiches
(Published on 4. October 2025, 22:23 by flutchman)
Yin Yang Skyscrapers
Yin Yang X-sums
Rules
• Normal sudoku rules apply.
• Yin Yang: colour the grid using two colours, such that all cells of the same colour are orthogonally connected, and no 2x2 area is fully one colour.
• Sandwiches: clues outside the grid give the sum between the lowest and the highest digit in that that row or column.
• Coloured sandwiches: each sandwich clue only sees digits of one yin yang colour, while digits of the other colour are completely meaningless for that clue.
Which colour corresponds to each clue must be determined.
Note: you may place colours or labels outside the grid to assist your solve. Those won't interfere with the solution checker.
Note note: the two 12 clues in row 9 refer to different colours.
Rules example, with orange and blue as yin yang colours:
Have fun and keep flutchin'.
Yours, Dying Flutchman
Please click the image to solve.
Solution code: Col 5.
Enter 9 numbers, with each switch in yin yang colour indicated by a *.
E.g. the example row above would give: 7*94*15*6*28*3
Comments
on 9. October 2025, 20:59 by AdarshN
Great puzzle! Took a while to puzzle through—the degrees of freedom at the beginning are intimidating—but every deduction is totally fair and very satisfying.
on 7. October 2025, 10:15 by flutchman
Minor fix to avoid colouring ambiguity in the end game.
on 7. October 2025, 09:36 by SeveNateNine
Nice puzzle, but it seems to me like the coloring can go either way for the 1 and 4 in box 1. Especially since the c2 clue is valid either way in my solution.
Wow, can't believe I missed that. That's terrible. But I think I have it fixed now.
Thanks a lot!
on 6. October 2025, 20:34 by flutchman
Added rule clarification.
Tnx Q.
on 6. October 2025, 19:44 by Qodec
Fantastic puzzle! Perhaps good to mention that the two 12 clues in row 9 don't refer to the same sandwich.
on 6. October 2025, 14:15 by marcmees
very nice. The double clues offer few possibilities. Hence < 5* (imo). Thanks
on 5. October 2025, 17:09 by bansalsaab
Amazing construction.
on 5. October 2025, 13:04 by marcmees
Q: clues are placed in correct order or @ random?
Always the smallest clue inside, so basically at random. DF
on 5. October 2025, 12:44 by Snookerfan
Very nice! I found it very hard, especially a few steps in the mid-solve. Thank you
