When tea drinkers tap the table with two (occasionally three) fingers of the same hand, an action known as finger kowtow, it is an expression of gratitude to the member of the party who filled their cups.
According to legend, this gesture recreates a tale of Imperial obeisance and can be traced to the Qianlong Emperor, a Qing Dynasty emperor who used to travel incognito. While visiting South China, he once went into a teahouse with his companions. In order to maintain his anonymity, he took his turn at pouring tea. His stunned companions wanted to kowtow for the great honour but to do so would have revealed the identity of the emperor. Finally, one of them tapped three fingers on the table (One finger representing their bowed head and the other two representing their prostrate arms) and the clever emperor understood what he meant. From then on, this has been the practice.
