This song is about the legendary Japanese samurai Miyamoto Musashi (1584?1645), considered by some to have been the greatest samurai who ever lived. He is said to have won his first duel at the age of 13, devoting subsequently the rest of his life to perfecting his swordsmanship. Spending most of his time travelling and pondering, he was also a painter who specialised in self-portraits and landscapes. In his later years he authored the Book Of Five Rings which details the art of sword combat, and is alluded to in the song. This is another song that is disliked by many Maiden fans and, along with 'Quest For Fire', it has never been played live in concert.
Bruce wrote the lyrics to that. It's basically about a Japanese guy who builds himself up to a peak of fitness and wants to kill himself hara-kiri style. I think it would be a good live song but we have never played it on stage as of yet.