Koryū (古流:こりゅう), meaning “traditional school”, or “old school”, refers specifically to schools of martial arts, originating in Japan, either prior to the beginning of the Meiji Restoration in 1868, or the Haitōrei edict in 1876. In modern usage, bujutsu (武術), meaning military art/science, is typified by its practical application of technique to real-world or battlefield situations.
The term also is used generally to indicate that a particular style or art is “traditional”, rather than “modern”. However, what it means for an art to be either “traditional” or “modern” is subject to some debate. As a rule of thumb, the primary purpose of a koryū martial art was for use in war. The most extreme example of a koryū school is one that preserves its traditional, and often ancient, martial practices even in the absence of continuing wars in which to test them. Other koryū schools may have made modifications to their practices that reflect the passage of time (which may or may not have resulted in the loss of “koryū” status in the eyes of its peers). This is as opposed to “modern” martial arts, whose primary focus is generally upon the self-improvement (mental, physical, or spiritual) of the individual practitioner, with varying degrees of emphasis on the practical application of the martial art for either sport or self-defence purposes.
The following subsections represent not individual schools of martial arts, but rather generic “types” of martial arts. These are generally distinguishable on the basis of their training methodology and equipment, though wide variation still exists within each.