This is a rather old discussion, but it caught my attention, and I think something of note can be added. I have wondered about the proper spacing, hyphenation, or lack thereof for a long time, but I have always used "Isshinryu" simply because my sensei (Ed Johnson) used that form on all his documentation. However, by the rules of Romaji transliteration, separate words have a space between them, so the proper way to write it as a noun would be "Isshin Ryu". By the rules of English, if it is used as an adjective [e.g. Isshin-Ryu punch," it would be hyphenated. According to an English dictionary, "Isshin Ryu" become English words because they have been adopted into English from Okinawan; as such they are no longer subject to any Japanese conventions (when used in English). Romaji itself is a universal phonetic writing in accordance with its rules and conventions.