Miyamoto Musashi is touted as being the first to develop (or at least write about) a method of fighting with the katana in one hand and the shorter sword in the other. His treatise is the Go Rin No Sho, often translated as the Book of Five Rings (but Book of Five Spheres is more apt, since in Buddhist literature the Five Spheres were the four appendages of the human body, and the head).