In drinks in the tea custom to have one "knocks on refers to Also Ritual" the interesting rumor, fable Emperor Qian Long has time wears poor clothing so as to be inconspicious privately visits, Sunday on the clear teahouse drinks tea with the local official. After emperor pour out serves tea, also conveniently for Sunday clear pours out serves tea. Sunday clear immediately feels extremely flattered, also does not dare 跪謝 the dragon graciousness, perhaps exposes emperor under the big crowd of people the status. How should this be good? He thinks quickly in emergencies, with double refers to the flexure, knocks on 3 on the tabletop, replaces kneels down to kowtow the ritual. From this, then spreads to the folk, becomes one kind to be established by usage "thanks" the etiquette. This certainly is the fable, Qian Long life all has not possibly poured out the tea for oneself, much less conveniently poured tea to the person. Therefore the teahouse person pours tea 俾 the person, o each one person meets o is the cup isolation knocks □is has "thanks" with "should not" a meaning, is one kind of politeness performance.