Sudoku Sunday

This puzzle appeared in the 4/21 DC Examiner; it has a difficulty rating of five stars. I'm including it here because I found some interesting stuff going on in the bottom left corner.

Basically, I'd gone through the "brute force" method (i.e. figuring out the possible values for each square and annotating them) and found the same three numbers (e.g. 1,2 and 6) repeated in three cells in a row. Although I couldn't tell which number appeared in which cell, I knew that no other cells in that row could use those same numbers. I'd seen that same approach/technique with pairs of number in adjacent cells before, but never triples.

The solution is here for those of you who don't have the time or patience to work through it.