Friendly Indexers
(Published on 1. June 2023, 06:18 by thoughtbyte)
Note: I recommend trying the slightly more difficult version of this puzzle here: https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000E3G. While the puzzles share a lot of the same logic, I think the miracle version is better.
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.
Diagonal: digits cannot repeat along the indicated diagonal.
Minimum: cells with arrows facing inward must contain numbers less than all orthogonal cells.
F-Puzzles: https://f-puzzles.com/?id=2zlut9x7
SudokuPad: https://tinyurl.com/friendlyindexerssudoku
Solution code: Row 9.
Comments
on 6. July 2023, 23:29 by thoughtbyte
adjust difficulty
on 6. June 2023, 01:05 by thoughtbyte
Add note.
on 5. June 2023, 16:45 by thoughtbyte
Thank you for the comments, I'm glad you enjoyed the puzzle! This one felt like a discovery.
on 5. June 2023, 16:44 by thoughtbyte
update difficulty
on 5. June 2023, 15:07 by JayForty
I would also say that if you're not familiar with global indexing rules in general and friendly cells in particular, it's a very hard puzzle. There are a few quite unintuitive implications of the rules to discover :)
on 5. June 2023, 14:54 by JayForty
Crazy puzzle! In a good way. Mind-bending and seemingly impossible, yet it has a beautiful and very satisfying logical path through it. A brilliant creation!
on 4. June 2023, 18:12 by MrRobotMan
Once wrap your head around the implications of the indexing rules this puzzle flows phenomenally. To clarify something about the rules that I didn't get at first, all friendly cells MUST be indexing cells. For example: if R5C2 is a 4, R4C5 must be a 5 and R5C4 must be a 2.
on 1. June 2023, 12:27 by sanabas
Took a little while to wrap head around how the rules restricted things, and it is very easy to make a mistake. But once both those things were sorted, it flowed really well, very interesting logic.
