Normal sudoku rules apply. Draw a 1-cell wide loop that moves strictly orthogonally and doesn't branch or intersect itself. The loop doesn't touch itself, even diagonally. The loop acts as a German whispers line. Neighbouring digits on the loop must have a difference of at least 5. A digit in a circle indicates how many times that digit must appear in circles. The circled digits also indicate how many of the up to 8 surrounding cells are on the loop. Circles are never on the loop.