Three choices
- Arrows
- Region sum lines
The brief
Normal sudoku rules apply. A circled digit indicates exactly how many circles contain that digit. (Note: This also includes circles with emerging arrows.) The red line is a region sum line, i.e. in each 3x3 box it passes through the digits on the line sum to the same value. Digits on an arrow sum to the digit in the circle from which the arrow emerges.