Many arts have a ranking system. A typical ranking from beginner to most experienced master is: 10th kyu, 9th kyu, ..., 2nd kyu, 1st kyu, 1st dan, 2nd dan, ..., 10th dan. "kyu" and "dan" are Japanese words; Korean systems use the word "gup" instead of "kyu". 1st dan and above frequently wear black belts.
Sayokan uses SAN instead of DAN or equivalent. It's related to the Turkish culture as it is in others above. We don't have KYU, instead we use TOY. Sayokan starts from 5th TOY and goes up to 1st TOY then 1st SAN (black belt. See the SAN Grading in this site.