It has somewhat to do with emptiness and a lot to do with the zen inspired focus in the art of living. Being in the present moment and totally immersed in what you are doing in that particular moment. It can't be said that the Zen Buddhist tradition was particularly central to the samurai, perhaps not in the traditional zen sense. Obviously they were not monks, though perhaps they became monks at some point, but their philosophy was built upon the concept of Bushido which we can relate to the concept of chivalry in the west. It was the code of the warrior-poet ideal. Miyamoto Musashi was a great and undefeated warrior many centuries ago who has written a book called The Book of Five Rings and I would urge you to read it to better understand the ideology and ideal of the samurai. Also, if you are interested in Bushido, I encourage you to read Nitobe InazÅ's Bushido: The Soul of Japan. http://www.leader-values.com/article.php?aid=546 Here is a nice article on Musashi and his philosophy.