The Sash Ranking System used at our school is as follows:
No Sash, White, Yellow, Orange, Purple, Blue, Green, Brown, Red, then Black. White, Yellow, and Orange is based upon the concepts introduced in the Sil Lim Tao Form. Purple and Blue is based on the Chum Kiu Set. Green and Brown on the Biu Jee Set. Red (Wooden Dummy), Black (Long Pole), and upon learning the Butterfly Sword Form and applications (Bat Jam Do) the student can evaluate for their Certificate of Completion -- which means that they are qualified as a Sifu in Wing Chun.