This paper will rethink the cause of the initial schism in Buddhist monasteries, a long-standing controversial problem, mainly with the help of two persuasive works, one an ancient text, the ?āriputraparip?cchāsūtra, which belongs to the Mahāsā?ghika, and the other a modern work by Bareau[1955a]. In explaining the characteristics of the subjects of the primary schism, Bareau[1955a] pays special attention to the general agreement of the accounts of the related materials, which always relate that the conflict was caused by the environmental differences between two groups, one a western group and the other an eastern one, although it is unclear which was the Sthaviravāda and which the Mahāsā?ghika, notwithstanding the arbitrary assumption by Hofinger[1946]. Bareau claims that the eastern monks must have lived a much more comfortable life provided with sufficient daily needs or facilities by a greater number of lay people as compared with the western monks, who seem to have been compelled to live an austere way of life in a rather infertile environment. This suggestive observation leads us to another chronicle text, the ?āriputraparip?cchāsūtra, which informs us that there was a serious conflict between the Sthaviravāda and the Mahāsā?ghika concerning the question of whether it was possible to increase the number of pātimokkadhammas, with the latter severely accusing the former of arbitrariness in expanding the rules. This argument shows remarkable agreement with the fact that the number of rules in the existing Mahāsā?ghika Vinaya is much smaller than that of the existing Sthaviravāda Vinayas. What is crucial here is that the difference in the number of rules is primarily rooted in the number included in the sekhiyadhammas, the Sthaviravāda Vinayas having almost twice the number of the Mahāsā?ghika Vinaya. Sekhiyadhammas are rules which are mainly concerned with the behavior or etiquette required of monks in daily life, especially in the presence of lay people, and most likely seem to have been compiled with the intention of keeping monks in the favor of laymen. The increase in the number of sekhiyadhammas in the Sarvāstivāda or Mulasarvāstivāda Vinaya is therefore considered to reveal their tendencies to rely on supplies by donations, not their adherence to an austere life. All the relevant materials considered, a single cause of the first schism seems not only difficult to discover, and has not been to this day, but also less likely to have existed. In the course of time, as the Buddhist monasteries expanded, differences derived from local distinctions must have been so distinctively manifested that all monasteries could not maintain their coherency and, as has been pointed out by Bechert[1982] with respect to sīmā, gradually divided one from another. The ?āriputraparip?cchāsūtra and the extant Vinayas suggest that this conjecture is highly possible.
