Sado, also called chanoyu, is a custom of entertaining guests with tea. Tea culture is one of the essential Japanese culture. It was established during the Azuchi-Momoyama Period (1573-1603) by Sen-No-Rikyu. There are mannerisms regarding the technique the master must use to make the tea. The details are sometimes very subtle. Importance is also placed on the guest's gestures upon drinking it. It is not a simple act of entertainment, but rather considered a form of art in which the exchange of manners becomes a symbol of thinking about the way of life. It's quite deep.