Friendly Indexing Miracle
(Published on 5. June 2023, 18:29 by thoughtbyte)
This is a more difficult version of my previous Friendly Indexers: https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000E1W.
To my surprise, this miracle version still solves, and the logic is even more beautiful in my opinion. This felt like a discovery.
Normal Sudoku rules apply. Additionally:
Friendly indexers: A friendly cell is a cell which contains its row, column, or box number. All friendly cells are column AND row indexers, and they must index at least one cell other than itself.
Column indexing: friendly digits in column X indicate the column in which the digit X appears in that row. For example, if r4c2 is a 4, r4c4 is a 2.
Row indexing: friendly digits in row X indicate the row in which the digit X appears in that column. For example, if r3c5 is a 5, r5c5 is a 3.
Additional example of a friendly indexer: if r3c6 is a 2, then r3c2 is a 6 and r2c6 is a 3.
Diagonal: digits cannot repeat along the indicated diagonal.
F-Puzzles: https://f-puzzles.com/?id=2kcwqmv3
SudokuPad: https://tinyurl.com/friendlyindexingmiracle
Solution code: Row 9.
Comments
on 15. June 2023, 22:39 by mathpesto
Had to sit with this for a few days. It took me a while to wrap my head around everything, but wow! Such an incredible setting. And yes, my notational approach was a nightmare, so I agree with Playmaker's forewarning.
on 7. June 2023, 07:43 by Playmaker6174
It’s already insane how this grid has a unique solution, let alone the fact that it has a (wonderful) logical solve path :o
This one also shows how easy I can get bamboozled with indexers. For future solvers, proper pencil marks are highly recommended to make better progress.
on 7. June 2023, 02:20 by thoughtbyte
Thank you for the feedback, glad you liked it!
on 7. June 2023, 02:20 by thoughtbyte
Add another example.
on 6. June 2023, 21:06 by Myxo
Mad minimalistic puzzle, really enjoyed solving that!
on 6. June 2023, 01:49 by Bellsita
Wow that was tough! Amazing logic! That diagonal does so much. It's really miracle that this puzzle solves.
on 5. June 2023, 19:03 by thoughtbyte
Added note about difficulty.
