Oldest and smallest division of the Tripitaka .
It lays out the 227 rules of monastic life for bhiksus , along with an account of the occasion that led the Buddha to formulate the rule. It varies less from school to school than does the Sutta Pitaka or the Abhidhamma Pitaka . It includes an exposition of the rules, which are divided into classes according to the severity of the punishment for breaking them; texts that deal with such matters as admission to and expulsion from the order; and a classified digest of the rules in the other Vinaya texts.