Normal sudoku rules apply. Group Sums: A number in a small circle indicates the sum of the digits in the cells covered by the corresponding circle. These digits may or may not repeat. Arrow Sudoku: Digits along an arrow must sum to the number in the corresponding circle. In this Sudoku all group sum clues contain a comparison operator. The clue ≥26 for example indicates a sum of at least 26. An arrow between two cells points to the smaller number.