The most regarded virtue of the samurai was loyalty. Every samurai had a lord to whom he owed his loyalty. Even the shogun owed loyalty to the emperor/god. It is for this reason that the warriors of Japan acquired the name �Samurai�, one who serves. In feudal Japan the samurai had a �giri� or �on�, a debt, of fidelity to the lord who provided he & his clan the opportunities in/for life. "If he will only make his master first in importance," explains the Hagakure, "his parents will rejoice and the gods and Buddhas will give their assent. For a warrior, there is nothing other than thinking of his master." A samurai was honored if he served his lord in his life and in his death. No personal attainment or success could equal that service.
Gi
The samurai concept of morality was based on his words & actions, and their congruence. Once committed to a path the samurai must continue on it until completion, or until otherwise ordered by his lord. If he was unable to complete his duty to his lord the samurai was shamed, and the only alternative to maintain his honor was by seppaku.
In this case the selfless act is the barometer of morality. In that atmosphere justice/rectitude is the ability to make the choices that lead to those selfless acts. So, in addition to the correct choice the samurai also required the empowerment to enforce that justice. The samurai had been given the power of life and death over the common people.
Makoto
Sincerity is a form of truthfulness. For a samurai it was not just telling the truth it was living the truth. In martial arts, politics, social affairs, and in every step the samurai should be true to his word & deed. It is with this sincerity that a person can bring their best self forward. Idle words and actions were considered wasteful, and a weakness.
Rei
The Japanese forms of etiquette are very refined, and some may say effete. Japanese politeness and courtesy are best expressed from a sympathetic perspective. Care is taken not to do anything that would make another feel self-conscious or obligated. It is not just the forms that express rei, but the intention. Although Japanese forms of etiquette may seem burdensome and rigid, in time they can become a natural and spontaneous way to express makoto.
Jin
Benevolence or compassion was a prized quality of a samurai and daimyo. Especially, sense it was this class that ruled the people. Rather than solely relying on fear and military force a daimyo with jin could utilize good will as a technique to assist the populace in following him. The daimyo encouraged the samurai to study the arts to foster jin into their character. Thus the arise of great traditions in calligraphy, flower arranging, tea ceremony, and others. This gave a balance to the near constant warfare that the samurai was exposed to.
Yu
Bravery and courage are well regarded in all warrior traditions. The samurai examined courage through the prism of death. The samurai adage to not fear death does not imply foolishness. "To die without gaining one's aim is a dog's death and fanaticism," says the Hagakure.
Life at that time was difficult. Daily life for the samurai, and anyone really, contained deep uncertainty. We live with this same uncertainty today, but the security our societies offer allow us to avoid thinking of it. Ultimately the samurai didn�t really need to think about it either. Not because they could hide from it, but because they realized there�s nothing that can be done about it. From that perspective the acceptance of death allows actions to occur without hesitation, and thereby imbuing those actions with admirable courage.
Meiyo
Samurai honor is strongly associated with reputation. The lack of honor is shame and guilt. These demons eat away at dignity and self-esteem, weakening all actions & words of the samurai, his clan, and daimyo. Today it is still so. Our politicians always attack the ethical weaknesses/openings of their competition.
Honor is an elusive concept. That is, where do you draw the line. If you are insulted is your honor tainted? If the insult is from a child or by a coworker in the workplace does it make a difference? In feudal Japan someone who insulted a samurai was subject to summary execution. I think in this we can reexamine the virtue of gi. Being that the samurai was acting in selfless accordance to his lord this allowed the correct moral judgement to be determined by the ethics of feudal Japan. Therefore, outside of the personal ego, and in accordance to the service of his lord, the samurai could determine honor or shame clearly on a case by case basis.