Normal sudoku rules apply. (ie Every row, column, and 3x3 box must contain the digits 1-9 with no repeats.) Digits on an arrow spell out the coordinates for the digit that is their sum. The row number is written on the start of the arrow, the column number is written on the arrow tip. If, for example, an arrow looks like this: (14) then there must be a 5 in r1c4. All the arrows must correspond to different coordinates. Digits may repeat on an arrow if allowed by other rules.