... by: JosephYour paragraph that starts "Using the argument.." should say:
"Using the arguement above we know that one 5 or 3 will occur in B7 or A9 forcing the other cell in the top right box to be a 2.
You have it listed 5 or 2, but I think it should be 5 or 3, since one of them will be a 2 as you state correctly afterwards. I may be wrong, but that makes the most sense, especially following the logic in the bottom box.
Great site though! I love it-no Sudoku site comes close to being as good as yours!
Andrew Stuart writes:
Fixed ! ty