According to the book, Tang Soo Do History by Dan Segarra:
"In 1936 Master Yang Kuk Jin (楊鞠振/楊麴震) was a well-known master of northern Kung Fu particularly Tai Chi and Tan Tui... Master Yang trained them in Bo Bup (stepping methods), Ryun Bup (conditioning ...
This information may be out-of-date, as I completed my training around 1996 or so, but as of the last time I trained:
Kam Sah (white belt)
Giecho Hyung Il Bu (yellow Belt)
Giecho Hyung Il Bu Sang Gup (yellow belt stripe)
Giecho Hyung Yi Bu (orange belt)
Giecho Hyung Yi Bu Sang Gup
Giecho Hyung Sahm Bu (purple belt)
Pyong An Cho Dan (green belt)
Pyong An Yi ...