Normal sudoku rules apply. Digits along an arrow sum to the number in its circle. Digits along an arrow also act as an X-sum “clue”: the following X digits (in the direction of the arrow) sum to the clue, where X is the first cell in that direction. 2-cell arrows are double-digit clues: The nearest digit to the arrow circle is the tens digit, followed by the units digit. The inequality symbol ‘points’ to the smaller of the two digits surrounding the symbol.