Zen has long had a great influence upon Japanese culture. Many aspects of this culture are touched upon by Zen including art, literature, and specific ceremonies such as the one concerning tea. During the Kamakura period of Japan, another area of culture began to be affected by Zen; the martial arts of the samurai class.
Somewhere along the line, the samurai realized the ease with which the monks of Zen Buddhism dealt with issues such as mortality and then began to seek these methods of discipline for themselves for the purposes of becoming less concerned with their physical well-being. However, as D.T. Suzuki noted, it was " not mere recklessness, but self-abandonment, which is known in Buddhism as a state of egolessness." This is the ideal which the samurai warrior sought; a state of being wherein life and death were meaningless and all that he had to concern himself with was his duty to his master, or if he was ronin (rogue samurai without a master), with his duty to his own code of honor. In order for the Zen master to pass on this state of mind to the eager to learn samurai, the master had to equate the state of mushin (empty mind and egolessness) with something familiar to the warrior. And what is more familiar to a warrior than his weapon, most often a sword such as a tachi (long-blade), katana, or iaito? From the first time that a samurai blade is picked up by its owner until the day the owner dies, it is his goal to so completely master the blade and make it as much a part of him as his own hand that there is seemingly no effort in using it. As stated by Takuan, a Zen master from the Tokugawa period, "you must follow the movement of the sword in the hands of the enemy, leaving your mind free to make its own counter-movement without your interfering deliberation." Herein lies the simplicity of Zen teaching in respect to all things, both exceptional and common; think not, merely do.