Hagakure: The Way of the Samurai
by Yamamoto Tsunetomo
The Way of the Samurai is found in death. Meditation on inevitable death should be performed daily. Every day when one's body and mind are at peace, one should meditate upon being ripped apart by arrows, rifles, spears, and swords, being carried away by surging waves, being thrown into the midst of a great fire, being struck by lightning, being shaken to death by a great earthquake, falling from thousand-foot cliffs, dying of disease or committing seppuku at the death of one's master. And every day without fail one should consider himself as dead. This is the substance of the Way of the Samurai.
Yamamoto Tsunetomo
https://en.wikipedia.org/wiki/Yamamoto_Tsunetomo
Bushido
https://en.wikipedia.org/wiki/Bushido
The essence of bushido was defined by Saitō Chikamori as:
Sincerity - do not lie, do not be insincere, do not be superficial
Responsibility - do not be obsequious
Frugality - do not be greedy
Politeness - do not be rude, do not slander
Modesty - do not be boastful, do not be arrogant
Loyalty - do not be unfaithful
Harmony - be on good terms with comrades
Tranquility - do not be overly concerned with events
Compassion - show concern for one another, be compassionate, with a strong sense of duty.