I’m glad that you brought up Musashi and Zen ( I have the Cleary translation of The Book of Five Rings on my shelf).

As Japan’s greatest swordsman -perhaps the greatest in recorded history – Musashi wrote about his art in a way that expressed swordsmanship in terms of principles of combat and oneness with the moment so that the flow of the opponent could be intuitively grasped before he could undertake his next action. Principles that could be extrapolated to different levels of conflict. An individualist fighter, who understood his interconnectiveness with his environment and mental state, it’s highly probable his insights would have resonated with Boyd’s personal experience as a fighter pilot and subsequent ideas.