Normal sudoku rules apply. If there's a diamond between two horizontally adjacent cells, then the absolute value of their difference is the same as the first digit in that row. If there's a diamond between two vertically adjacent cells then the absolute value of their difference is the same as the first digit in that column. All possible diamonds are given. (Note that because there are no diamonds shown in this puzzle, there are no adjacent pairs whose difference equals the first digit in their row/column).