The Book of Five Rings is a book on his two-sword sword style, which has philosophical meanings beyond it. It is geared to the particulars of one-on-one conflict, although many of the strategic principles have broader philosophical and strategic implications. It is not a way of doing business, or an ethical system to live by though. Musashi teaches how to win at all costs, and in many cases has identified practical applications for the principles of the Art of War in a one-on-one conflict. It is a direct and honest book though and his viewpoint on individual conflict is realistic and developed out of experiences in many duels. His perspective is particular useful as a martial philosopher and strategist because he was personally and instantly affected by any erroneous beliefs he had about combat in his time. This is also the case with modern martial artists, though they can go on to write more afterwards about why something really didn't work.

Bruce Lee was extremely influenced by Jiddu Krishnamurti too. He read a great deal on ethics, philosophy, strategy- and martial arts styles and techniques.