Quote Originally Posted by XOR LX View Post
If a "K" appears in the first group of 10, say, does that mean this now reduces the 'need-to-mark' for that group from 4 to 3?

Or is it that all these first three conditions still apply, but that, from the final two choices to make up the 10, one of these must be that corresponding to the "K"?
Well it doesn't really reduce it from 4 to 3, but it also doesn't have to come from the final 2. Basically the difference in output would be if the cell adjacent to the "K" isn't in the 10 that would've been marked originally, it would then need to be marked instead of the 10th number (the 2nd number in the last step), however if the "K" cell is already marked, then the output would be the same. (But the minimum of 4 - 2 - 2 always applies).