Normal sudoku rules apply. Draw a one-cell-wide loop of orthogonally connected cells. The loop may not touch itself, not even diagonally. The loop acts as a German Whispers line (i.e., adjacent digits on the loop must have a difference of at least 5). Clues outside the grid are Japanese Sums ie they give the sums of loop segments in the respective row or column, in order, where cells not on the loop separate segments. A question mark indicates any digit from 0 to 9, but no clue may have a leading zero. An asterisk denotes an arbitrary number of Japanese sum clues. This could be zero, one, or multiple.