Imitation or Convergent Evolution

When I was living in Japan many years ago, I came back to California on occasion to visit Toshihiro Oshiro, my Yamanni Ryu bojutsu sensei. I remember during one such visit, Oshiro started to teach me a particular technique that I swore I saw before. I forgot the exact technique it was, but the concept behind it had to do with sliding the hands up and down the length of the shaft in order to maximize the length of the part of the weapon that attacks the opponent. It was something I had been doing in both ryuha for years, but the “new” way he executed that particular technique (it was new to me, not him) was remarkably similar to a Tendo Ryu naginata-jutsu technique that my naginata sensei had shown me just before I left Japan.

“This is almost exactly like what Miyagi-sensei showed me last week on Okinawa!” I said in amazement.

He looked kind of puzzled, no doubt because what he was showing me was a signature Yamanni Ryu move. He asked if I could demonstrate what I meant.

So, using a nearby bo to represent a naginata, I demonstrated the Tendo Ryu technique to him. When I was finished, I saw him nodding in agreement that, indeed, they were similar.

“Sensei, they’re almost identical,” I said. “Do naginata and Yamanni Ryu bojutsu have common roots?”

He looked at me as if I was stupid.

“Of course they’re similar,” he said. “The two weapons have similar characteristics.”

The naginata and bo are both polearms, I knew, but his knowledge didn’t shed much light on my question. After all, there were other Okinawan bojutsu styles I’d been exposed that had nothing like what he was showing me. Yamanni Ryu bojutsu, an Okinawan martial art, seemed to have much more in common with Japanese naginata-jutsu and some Chinese staff fighting styles than any of the other bojutsu styles on the island … at least in this case.

After a few moments, I looked at him as if I was stupid.

Just because certain techniques in different styles look similar doesn’t necessarily mean one had any influence on the other, he continued.

“All humans have two arms, two legs, one heart and one head,” he said. “There’s only so much variation they can create given similar tools and similar purposes.”