Insider (10x10)
(Published on 2. November 2022, 17:35 by M.K.)
Rules:
- Every row, column, and region must be filled with the digits 0 to 9 once each.
- Yin Yang: Shade some cells in the grid such that all shaded cells are connected and all unshaded cells are connected. No 2x2 box may be fully shaded or fully unshaded.
- Inside a region, all shaded cells must be connected and all unshaded cells must be connected.
- There are 10 "insider" digits – one per row, column, and region. A shaded insider represents the sum of the unshaded digits in that region, and vice versa.
- Each insider has a twin. For example, if a shaded 5 is an insider, there is exactly one unshaded 5 that is an insider.
Link: SudokuPad
Solution code: Row 5 + Column 5
Comments
on 19. March 2026, 20:52 by M.K.
Added solution checking.
on 5. November 2022, 21:30 by Gnosis66
Excellent, very fun puzzle. I was baffled at first how to begin. The different elements of the rule set kept surprising me in the way they worked together.
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It's meant to be baffling in the beginning. Understanding the intertwining nature of the rules is part of the concept. I'm glad you enjoyed it! (M.K.)
on 4. November 2022, 00:06 by MagnusJosefsson
Very fun concept and very pleasant yin-yang start. Second half is much tougher and has a good but narrow logical path with some cool logic regarding the insiders.
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Thanks for solving! (M.K.)
on 3. November 2022, 11:04 by M.K.
German version now links to the puzzle with german rules. Also rephrased the rule about the shading inside a region, as the provided example was misleading.
on 3. November 2022, 05:02 by vitaminz
Loved the very opening coloring. It seemed impossible for a long time (bad assumption on my part) and was a very pleasant breakthrough. I'm always amazed at how people can build puzzles that make you work for almost every digit even up to the end. Very well constructed!
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Thank you! I aim for challenging puzzles that utilize the 0 in a meaningful way. I'm glad that they are enjoyable! (M.K.)
on 2. November 2022, 22:01 by M.K.
Corrected labels and tags.
