Dating back to 1645, The Book of Five Rings has been translated and republished many times, and expands well beyond its initial following of the practice of martial arts. It is considered the classic text of general martial arts, but has also gained acclaim by business and thought leaders who respect its perspective on conflict resolution. Written by Miyamoto Musashi, The Book of Five Rings strives to connect philosophy with diligent practice. The work is essentially compromised of five separate parts, or books, as the master would teach his own students. He separates his thoughts into the Book of Earth, the Book of Water, the Book of Fire, the Book of Wind, and finally, the Book of Void, exploring the ultimate achievement of perfect zen.
This must be researched heavily.
I think this was written about 809 times in this book. Still some good nuggets in there though.