The Kata Ryufa is a version of regarded as the Tachemura (Takemura) version of Passai Dai, it is believed to have been passed from Soko Kishomoto to Seitoku Higa of the Bugeikan and Seiken Shukimune of Gensei Ryu. The Gensei version has been modified and called it Shukumine No Passai. There is also a Seiichi (Shikan) Akamine version and various versions of that, the original version from that line came from Shukimune, although there are other claims, but these in my opinion are unsubstantiated. Ryufa forms part of a set of Kata known as the Takemura or Kishomoto line. Not sure what else it is that you may want to know about Ryufa.