I was the same Diane, went on a cruise round the Eastern Mediterranean and a bit of time in Italy and Spain for a month, had a bit of catching up to do. All caught up now.

Fun Expert ... one-guesser for me :

Needed a second guess, first one got a long way but wasnt the right one in the end

Phil, I wish I had been on your trip! I was swamped with work Im nearly 75 - whats wrong with that picture and overwhelming distress over the state of my country.

Very hard but no greens . . One guess.

Taking off soon for a South Pacific cruise and will be gone for more than a month. I will have some catching up to do. But Im looking forward to playing more than one IronSudoku a day.

With greens this expert moved quite quickly but required guesses at two separate choke points.

Actually it can be done wiyhout guesses..box 9 has two possible locations for the 8 but one of them leads to a quick contradicrion.

@MrOoijer, if I have to choose between two possible positions of a 8, and I eliminate one position by testing it, I publicly count that as a guess - but only because everyone else seems to. Privately I think of an either-or test as a valid approach to methodically eliminating possibilities until only one possibility remains - like Sherlock Holmes. To me, real guessing refers to placing a number in a cell because it looks like it might work but without a supporting chain of reasoning. I have known other people to play Sudoku that way but have never seen the point of it.

In this specific expert I tested the 39 pair in box 5. My first test produced a quick contradiction. The other option seemed to leave me hanging and so I used another either-or guess to complete the puzzle. I have since tried again with the same 39 pair and found that my second guess was unnecessary. I now agree with MrOoijer - this is a one-test expert.