Standard arrow sudoku rules apply. That is:
1) Normal Sudoku rules apply.
2) Digits along an ARROW must sum to the digit in the associated circle
You can play it here: f-puzzles. Or here: CTC-App
HINT #1 for break-in (highlight below):
Use SET
HINT #2 for break-in:
Use SET on columns 2,3,4,5
HINT #3 for break-in:
Use SET on columns 2-5 and rows 1,6,7,8,9. Look at minimizing and maximizing what is left.
Solution code: Row 3 + Row 9 (18 Digits)