Reddit mentions of Secrets of the Samurai: The Martial Arts of Feudal Japan

There are enough similarities between Lee and Musashi to warrant some reading. What I find particularly interesting about both men was that they were nonconformists who came from cultures where nonconformity is frowned upon. Both were regarded as outright renegades by a number of prominent people who felt they disrespected martial tradition, and both reacted to this criticism by saying they made use of whatever was expedient at the time rather than what looked good. It's funny that these anti-traditionalists are now among the greatest celebrities that China and Japan have produced.

It's true that Musashi did not fight barehanded in his duels, but as a samurai, he would had had some grappling instruction at a bare minimum. According to historical accounts, he nearly incapacitated his first opponent by seizing his body and throwing him to the ground, which sounds like he used a suplex (don't know the Japanese term.) He also used psychological warfare to great advantage, habitually showing up late for duels with renowned and prideful warriors, who in due course became enraged at the slight; today, we would call Musashi's strategy "passive-aggressiveness."

Here's the Musashi biography I read some time ago. Read it if you're interested.

And if you're up for it, here's the still-definitive book on the martial arts of feudal Japan, which is relevant here because among other reasons, it shows ju jitsu techniques being used in their original context. If you've studied martial arts, you'll find it interesting throughout. The illustrations are fantastic.