Normal 6x6 sudoku rules apply. (Place the digits 1 to 6, once each, in every row, column and outlined box). Boxes are numbered in normal reading order. Orthogonally adjacent digits must not sum to their box number(s). For example, r2c4 and r3c4 must not sum to 2 or 4. Additionally, diagonally adjacent digits within the same box must not sum to their box number. The inequality sign points to the lower digit.