Normal sudoku rules apply. Cells with a solid grey square contain an even digit. Cells with a solid grey circle contain an odd digit. The circle or pill in box N records the sum of all the digits within box N that are orthogonally adjacent to the digit N within the box. Two digit totals are read left to right, top to bottom. For example, the pill in box 6 contains the sum of each digit that is BOTH in box 6 and orthogonally adjacent to the 6 in box 6.