Zip to N
The brief
- Normal sudoku rules apply, i.e. each row, column, and 3x3 region has to contain the digits from 1 to 9 once each.
- Zippers: On a lavender line, digits at the same distance to the center (marked by a dot) must add to the same sum. If the line has odd length, that sum must equal the digit at the line's center.
- Up to N-sums: A clue outside the Row or Column N indicates the sum of all digits up to the cell that contains the digit N. (The digit N itself is not included in the sum.)