The Hagakure (Japanese for Hidden by the Leaves or hidden leaves) is a collection of saying and wisdom written by Yamamoto Tsunetomo, former retainer to Nabeshima Mitsushige, the third ruler of what is now the Saga prefecture in Japan.
The Hagakure is meant to be a primer for young Samurai. The book records Tsunetomo's views on bushido, the warrior code of the Samurai. Hagakure is sometimes said to assert that bushido is really the "Way of Dying" or living as though one was already dead, and that a samurai retainer must be willing to die at any moment in order to be true to his lord. His saying "I have found the way of the warrior is death" was a summation of the willingness to sacrifice that bushido codified.
Full text of the Hagakure http://exhibita.com/Misc/hagakure/