Divide the grid into 9 regions, each consisting of 9 orthogonally connected cells. Place the digits 1-9 exactly once in every row, column, and region. The digits along the arrow sum to the three-digit number displayed in the attached pill. The arrow passes through the centres of all cells that are not part of the pill (note that consecutive arrow cells are not necessarily adjacent; for example, a portion of the arrow follows r7c1 → r7c3 → r8c1). The arrow functions as a ‘region sum line’: along the arrow, every maximal sequence of digits within the same region has the same sum. I.e. when all non-pill cells are arranged in sequence according to the order in which the arrow visits their centres, this sequence will be composed of disjoint contiguous segments with equal sums. Two consecutive cells in this sequence belong to the same segment if and only if they are part of the same region. The inequality sign points to the smaller digit.