Here are two puzzles where the clues are the least common multiples of the entries in those cells. For example with a clue of 15, the numbers would have to be 3 and 5 in some order. With a clue of 6 the numbers could be 1 and 6, 2 and 6, 3 and 6, or 2 and 3 in either order. The first one is pretty easy once you get used to the LCMs. The second I'd guess is more medium difficulty (probably still easy for the people on this site!) Feel free to let me know.
Puzzle One
Puzzle Two
There's no "if and only if" component this time. Lack of a clue doesn't mean anything, and in the second puzzle the clues are minimal. Take any one out and the puzzle loses its unique solution!
Solution and more info at: https://quadratablog.blogspot.com/2020/ ... udoku.html