The spear has always seemed to me the most underrated of the classical weapons, and Hōzōin-ryū is the school that makes the case for it best. There is a tendency to picture the samurai as a swordsman, and the sword as the soul of the warrior, but on the actual battlefield the spear was the more important weapon, and a school that has kept a complete and sophisticated spear method alive is preserving something closer to the real practice of war than many of the more celebrated sword traditions.
I am charmed, too, by the fact that this art was founded by a monk. The warrior-monks of the old temples are easy to romanticise, and I try not to, but In'ei seems to have been a genuine martial innovator rather than a legend, and the invention credited to him, the cross-spear, is a real and clever piece of design. The story that he conceived it while watching the crescent moon reflected in a temple pond is exactly the kind of poetic origin tale I would normally treat with suspicion; yet here the weapon itself is so distinctive, and the tradition so continuous, that the legend can be enjoyed without being mistaken for history.
What gives me confidence in the school's deep history is the company In'ei kept. He studied alongside Yagyū Munetoshi under Kamiizumi Nobutsuna, the founder of the Shinkage-ryū, and that is not a vague claim but a well-attested connection between figures who shaped several of the most important traditions in Japan. When a founder can be placed so firmly among his documented contemporaries, the early history of his school rests on something much sturdier than the usual founding myth.
I am careful, on the other hand, about the Musashi connection. Anyone who has read the famous novel, or seen the films drawn from it, will remember Musashi testing himself against the spearmen of the Hōzōin, and it is a wonderful set of scenes; but it is fiction, written centuries later, and it tells you about the school's hold on the imagination rather than about its history. Keeping the two apart is exactly the kind of discipline I think a reference owes its readers.
In the end what moves me most about Hōzōin-ryū is simply that it has survived. A complete method for a weapon that left the battlefield long ago is still taught and demonstrated in the city where it was born, by people who have kept it whole. That continuity, more than any legend, is the thing worth honouring, and it is the reason a school of the spear deserves a place beside the great schools of the sword.