Being as Korean, and Japanese both belong to the Altaic family of languages, they share some similarities, ryu is one of those, along with shin (mind/body), and some other terms. PaSaRyu comes from the older TKD, and though Master Rhee holds high rank with the Kukkiwon, he does not teach Kukki TKD. PSR has many of the same forms used in TSD in addition to forms from Gung Fu, and two man sets. fwiw, --josh