Normal sudoku rules apply. Box borders divide the blue line into segments. Digits on each segment along the blue line have the same sum. The digit in a red cell gives the placement of that cell's column number in its row (i.e. if row 6, column 5 contained a 9, that would place a 5 in row 6, column 9). The digit in a blue cell gives the placement of that cell's row number in its column (i.e. if row 6, column 4 contained a 9, that would place a 6 in row 9, column 4). Digits in cells with Stars are odd.