Through The Looking Glass
-Ordinary sudoku rules apply.
-Little Killer rules apply. The sum of the digits along the indicated diagonal is indicated. Digits may repeat along the diagonal.
-Looking glass rules 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.