Normal Sudoku rules apply. The clues outside the grid give the maximal length of an ascending subsequence of digits along that direction, where a set of digits is called an "ascending subsequence" of a row/column, if the order in which it appears in that row/column coincides with its natural ordering.
To give an example of that last bit, if a row reads 192837465, it could be clued as 5 from the left, since there are two ascending subsequences of that length (12346 and 12345) but no longer ones.
You can solve it online at F-puzzles or CtC.
Enjoy! :^)
Solution code: Row 5 (left to right)
on 31. January 2022, 14:59 by ElimGarak
Nice puzzle.
[Thank you! :^)]