The Book of Five Rings (Unabridged‪)‬

The Book of Five Rings is a text on Kenjutsu and the martial arts in general, written by the Japanese swordsman Miyamoto Musashi around 1645. There have been various translations made over the years, and it enjoys an audience considerably broader than only that of martial artists and people across East Asia: For instance, some foreign business leaders find its discussion of conflict and taking the advantage to be relevant to their work in a business context.  

Musashi establishes a "no-nonsense" theme throughout the text. For instance, he repeatedly remarks that technical flourishes are excessive and contrasts worrying about such things with the principle that all technique is simply a method of cutting down one's opponent. He also continually makes the point that the understandings expressed in the book are important for combat on any scale, whether a one-on-one duel or a massive battle.