Bobbin Winding Method (Figure-Eight Knot)

A thread-winding technique where, when the bobbin is down to the last fifth, the thread is manually wrapped back in the opposite direction around the bobbin to form a figure-eight knot before continuing. Invented by Song Nian and taught to her coworkers. Zhang Yalan and Zhang Man stole this method and claimed it as Zhang Man's achievement to secure a commendation.