In Japan, both real life and fictional dramas usually involve the conflict between duty (giri) and human emotion (ninjo).
Giri (義理) is the Japanese sense of duty — the unwritten social contracts that ensure social harmony.
The classic example of giri is the responsibility that Samurai had to their masters. A Shogun could ask anything of a Samurai — even that a Samurai take his own life. Samurai were bound by giri to obey.
More modern giri relate to work, family and interpersonal relationships. For example, if you work at a coffee shop it's your duty to provide good service to customers. If your customer happens to be a jerk — your duty remains. Japanese society finds it distasteful when staff assert themselves with customers.
Ninjo (人情) is the Japanese word for human emotion. In life (and fiction) ninjo often comes into conflict with giri.
The classic example, is the Samurai who falls in love with the Shogun's daughter. He is bound by duty to stay away from her. However, he's in love — his ninjo is running wild.
A more modern example could be a salary man who hates his job. He wants to quit to follow his dream of becoming a professional musician (ninjo). However, he has a family to support (giri).
A less dramatic example could be a waitress who has an obnoxious customer. Her giri tells to treat the customer with respect. Her ninjo tells her to spill a drink on him.
In Japan, old timers complain that young people have forgotten about giri and are driven by ninjo. When giri declines and ninjo escalates — social harmony is threatened (according to conventional Japanese thought).
Japanese culture is very different from Western culture. There are many concepts and ideas that are important to know when we read stories about Japanese characters.
One very important concept is the dual system of values called "giri and ninjo":
"Giri" means the Sense of Ought (what a person has to do). It refers to the obligation of duty and is an external value that includes the ethics of self-denial and behaving according to the demands of social order. Giri can be seen as a duty to the leader and as the value that patriotism is based on.
Ninjo, or feeling, is internal and refers to the emotional needs and desires of the individual, human affections, and natural feelings, for example, a relationship in a family.
The conflict of these two motives goes throught all the Japanese literature. One example is a scene where the warrior Shigemori is torn between his father's desire to fight the emperor, and hos own loyalty to the emperor: "If I am loyal, I cannot be filial (loyal to my father); if I am filial, I cannot be loyal".
According to a Japanese saying, "the most sacred relations (like a son and father) must give way before great duties". So when duty demands, the relationship between father and son just stops.
Everything must be sacrificed "on altar of duty". One's own interests, love, or welfare cannot be taken into consideration.
Giri includes the spirit of chivalry and self-sacrifice. A man who does not behave according to those principles is despised as a man who has no sense of giri. The samurai warriors were expected to be models of giri, or self-denial, even though they obviously had feelings.
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