"One who is supposed to be a warrior considers it his foremost concern to keep death in mind at all times..."
Bushido Shoshinshu was written by Taira Shigesuke around 1700 AD. Its purpose was to instruct the novice Samurai of the peaceful Edo Era, who had not known the rigors of battle, with the practical philosophies of previous eras. Bushido Shoshinshu is roughly translated as "Bushido for Beginners." The 1999 release from Tuttle Publishing sports the name Code of the Samurai. The modern translation was performed by Thomas Cleary.
While much less well known than the Hagakure by Yamamoto Tsunetomo (recently popularized by the Jim Jarmusch film Ghost Dog: The Way of the Samurai) Bushido Shoshinshu provides a much more coherent narrative style. Instead of being split into hundreds of aphorisms, anecdotes and Zen-like koans, Tsunetomo's text provides a step-by-step analysis of the proper path to following Bushido. While his conclusions and convictions are essentially the same as those found in the Hagakure, the more logical style and sequence are somewhat easier to digest.
The key idea behind both of these texts and the Bushido ethic, is that the way of the Samurai lies in death. It is through the constant awareness of death and its inevitability that the virtues of the Samurai flow. The highest and most essential of the virtues is absolute loyalty and fealty to ones master. It is the duty of every retainer to be willing to sacrifice his life for the honor or whim of his master.
According to Shigesuke, failure to keep death in mind at all times leads to laziness, sex addiction and basically the entire gamut of the Seven Deadly Sins. I actually find his reasoning on these points to be quite sound. Aside from such abstract concepts as the role of the mindfulness of death in maintaining knightly virtues, Bushido Shoshinshu has many minor and domestic details. These range from how to clothe and feed your servants to the proper Samurai approach to tea ceremony.
"...If you violate this covenant and act disloyally or unjustly, be sure that I will disown you, even though I am under the shadows of leaves and grass."
All quotes and sources taken directly from the text of the Bushido Shoshinshu