Hello. I am very interested in the mathematics behind these puzzles. I am happy to see so many people interested in the number of possible puzzles and the number of clues required to see a unique solution.

My question that I have been working on the past few days is a little different: What is the maximum number of clues that can be given without the puzzle having a unique solution? In other words, what is the limit on the number of clues such that one more clue will result in an inevitable unique solution.

If this has already been posted, sorry to waste your time.

~Thomas