In ancient China, war left a third of the population dead. Leaders searched for a new way of governing. Sun Tzu's recommended a strategic method to win that rarely required actual war. Spies, diplomats, deception, and a correctly organised internal structure were his tools. If it came to war though, he had detailed insight into its methods and strategies. Later, in Japan, samurai Miyamoto Musashi was literally unbeatable. One time, using his two sword technique, he single-handedly beat over 30 samurai simultaneously attacking him with guns, arrows and swords. Alone in a cave he wrote The Book of Five Rings, a classic that is still used by modern executives and martial artists.