Through the Looking Glass

As far as I know, this is a novel variant with some very interesting logic.

-Ordinary sudoku rules apply.

-Little killer rules apply. The arrows indicate the sum of the digits in the direction of the arrow. Some sums may contain the same digit more than once.

-Looking glass rules (new!) apply. Each digit (1-9) has a "buddy" that appears in all of the cells where the row and column indices are swapped. For example, if 1's are buddies with 4's and there is a 1 in r5c2, then there must be a 4 in r2c5. Ones being buddies with fours implies that fours are buddies with ones. It's possible for a number to be it's own buddy. Figuring out the buddies is part of the puzzle.

This is really a very simple rule, but if you are confused by my explanation or have clarifying questions, please let me know.

try it here

Watch a solve from Mark Goodliffe here