Normal Sudoku rules apply. The given filled circles indicate the start of a palindrome line (with the same order of digits from either end) The number in the circle indicates the sum of all the digits on the palindrome line. The arrows indicate the starting direction of the line. Empty circles are the ends of lines. The line paths and lengths must be discovered by the solver. Lines can cross each other but can not share cells. No digit repeats on a palindrome more than once.