The Japanese have two words: "UCI" meaning inside and "Soto" meaning outside. UCI refers to their close friends, the people in their inner circle. Soto refers to anyone who is outside that circle. And how they relate and communicate to the two are drastically different. To the Soto, they are still polite, and they might be outgoing, on the surface, but they will keep them far away, until they are considered considerate and trustworthy enough to slip their way into the UCI category. Once you are UCI, the Japanese version of friendship is entire universes beyond the average American friendship! UCI friends are for life. UCI friends represent a sacred duty. A Japanese friend, who has become an UCI friend, is the one who will come to your aid, in your time of need, when all your western "friends" have turned their back and walked away.

The Japanophile's Handbook