Musashi

The Go Rin no Sho is an important and useful work for the martial artist or anyone engaged in conflict, but value it for what it is and recognize what it is not.

It is not a moral or ethical guide. 'Kensei' gets translated as "sword saint" but Musashi was no saint-- he was a murdering bastard who, late in life when he felt death closing in, attempted to recreate himself, elevating his murders to duels and his insights to enlightenment. No where but in tales of Musashi's life is hitting someone over the head from behind as he is preparing for a duel seen as an example of sword skill or as masterful strategy. Were I to challenge you to a sword fight to prove the superiority of my school and then say, "You first," and waved you through like a gentleman as we entered the arena and then whacked you over the back of the head with a sap, no one would call that act a duel or a masterpiece of strategy. It is only good strategy if the goal is simply to kill. If the goal is to show or improve skill, it does not serve.

That's the caveat-- but there are useful things in the book, things of value and ways to think and feel and see.

Musashi's rules / my commentary:
1) Do not think dishonestly. Do not lie to yourself, ever.
2) The Way is in training. Work and learn hard, no one has ever improved by sitting on their ass and waiting.
3) Become acquainted with every art. Never pass up an opportunity to learn how an artist or skilled craftsman thinks or sees the world. Seek out the best and listen.
4) Know the ways of all professions. The world works because people do jobs. Learn about the jobs that make the world work and how they interconnect. Know ditch diggers and burger slingers, architects and doctors and understand how they need each other.
5) Distinguish between gain and loss in worldly matters. Know what matters. Protect what is truly precious, let go what is not. Do not lie to yourself about these categories or let society lie to you.
6) Develop intuitive judgment and understanding for everything. Trust your gut. Practice trusting your gut. Then practice deciphering your gut so that you can explain it verbally and you will develop intuition AND understanding.
7) Perceive those things that cannot be seen. Everything leaves tracks. Everything affects other things. When you learn to read the tracks, you can deal with invisible problems, like past trauma in a student.
8) Pay attention to trivial things. The tracks are in the small things, and small things affect big things. The tightening around your eyes will tell me more than a hundred of your words.
9) Do nothing that is of no use. My personal favorite- if you spend time doing something, it should make you or the world better. How many hours are wasted each day with TV shows that you won't remember next week or trivia or... how strong would you be if that time was spent working out? How much better could you make the world if the time was spent helping others?

There is more there in the book. Good lessons. None of which will help you a damn bit unless you practice them. Life is funny that way.