Oldest and smallest division of the Tripitaka .
It lays out the 227 rules of monastic life for 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.