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, not even diagonally. 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. Digits separated by a white dot are consecutive. Digits separated by a black dot have a 1:2 ratio.