The band of six monks is complex and controversial figure in the history of Buddhism. Though they are well acquired with both secular and Buddhist knowledges, they violate Buddhist precepts frequently and those are always denounced as "bad monks" by the Buddhist tradition. However, some Buddhist scholars nowadays re-interpret their misbehaviors as expedient which make rooms for the Buddha to prescribe or fine-tune the rules and regulations. Among various Vinayas, only Mūlasarvāstivāda-vinaya clearly provides the identity of the band of six monks and has abundant relevant information. Based on the Chinese Mūlasarvāstivāda-vinaya, this article attempts to describe the behaviors and activities of the six monks comprehensively, showing that they are prototype of a certain kind of "bad monk", so it is inappropriate to absolve them in term of "expedient".
