The Book of Five Rings
The Book of Five Rings (五輪の書, Go Rin No Sho) was written by Miyamoto Musashi. It is considered a classic treatise on military strategy, much like Sun Tzu's The Art of War.The five rings are Ground, Water, Fire, Wind and the Void. Each ring represents a different aspect of strategy, and by mastering all five rings, it is supposed that you make yourself invincible in combat. Although to members of the Hyoho Niten Ichiryu it is merely a manual of technique and philosophy.