The group-of-six-monks (abbreviated as ＂the group-of-six＂ thereinafter) is quite controversial personage in the history of Buddhism, whose are always denounced as ＂bad monks＂ , as they often go against the precepts. 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 the Mūlasarvāstivāda-vinaya clearly provides the identity of the group-of-six and has abundant relevant information. Based on the Chinese Mūlasarvāstivāda-vinaya, this article divides three groups and eight items, selects some examples for discussion, in order to show that the group-of-six have considerable knowledge of monastic discipline, but they stick to the literal meaning of the precepts and challenge other colleagues. As a result, some flaws of the Sangha order and loopholes of the precepts are revealed and given a chance for continuously improvement. Hence, it has showed the middle path and compassion of primitive Buddhism. As such, this is a noteworthy chapter in the development history of Buddhist monastic discipline.
