Prerequisite: Sense of Duty
This code of honor comes in three parts.
Hospitality. You respect hospitality highly, and if anyone visits you in your home, you are expected to feed him and give him a bed for the night without asking questions. On the other hand, if you accept someone's hospitality, it is polite to tell who you are and why you are there. No one is less respectable than an inhospitable person. You must even give hospitality to your sworn enemy, as long as he is under your roof.
Truthfulness. You strive to tell at least the letter, if not the spirit, of the truth. If you make promises, you fulfill them no matter the consequences. There is a proverb: "Eating a mouse includes the tail." Further, your word is your bond. You would rather die than break it. This also includes the oaths of your ancestors, because you believe yourself to be reincarnations of them!
Vengeance. If someone kills someone that you had a Sense of Duty toward, you must get revenge on either the individual or the group that condoned it, and it may not be by subterfuge. An open challenge to single combat is the usual way. You may never interfere with others' single combat, nor accept interference in yours.