The author’s book Indo Bukkyō Hen-i ron （インド仏教変移論）, published in 2000, clarified the changes that occurred in the management of the saṃgha in the Buddhist world before the Common Era, and proposed the theory that these changes triggered the emergence of Mahāyāna Buddhism later on. It consists of five major arguments, the second of which runs as follows.
There are two different definitions of a Buddhist schism （saṃghabheda） in the Vinaya materials: cakrabheda and karmabheda. The fact that the original definition of saṃghabheda was cakrabheda and it was later changed to karmabheda is substantiated by various sources, including the Vinaya texts, the commentaries to Vinaya texts and Sarvāstivāda Abhidharma texts.
In recent years, Akira Fujimoto has presented a critique of this argument. He has published three critical articles: a handout distributed to conference participants at the Annual Conference of the Pāli-gaku Bukkyō bunka gakkai, an article in Indogaku Bukkyōgaku kenkyū 70（1）: 47-54 and an article in Pāligaku Bukkyō bunkagaku 35: 21-53. The relationship between these three contributions, however, is extremely complicated and it is difficult to understand the overall structure logically.
A comparative study of the articles reveals that Fujimoto’s criticism is composed entirely of a combination of the following materials: a part of the distributed handout and the article in Indogaku Bukkyōgaku kenkyū.
The author has therefore scrutinized these and written a rebuttal to Fujimoto’s criticism （in Japanese）, which is a lengthy work of more than 240,000 characters. The author is currently considering how to publish it.
In the present paper, the author introduces one facet of his reply to Fujimoto. The passage the author discusses here is from the ‘Biqiu song’ 比丘誦 of the Sarvāstivāda Vinaya. There we read, “There are two kinds of saṃghabheda: karmabheda and cakrabheda.” However, Fujimoto says, “Only one type of saṃghabheda is mentioned here. Sasaki’s view that two different definitions of saṃghabheda presented here is incorrect.”
Fujimoto interprets the relevant passage are as follows. “There are two types of saṃghabheda: α and β. One is α + β （β is omitted here）. The other is α + β （α is omitted here）. Thus, although it appears as if there are two kinds, there is actually only one definition of a saṃghabheda. Why, then, does this passage omit α on the one hand and β on the other? In the first place, ‘omission’ is to omit of something obvious that could have been omitted in order to focus on something else.”
The mistake in his argument is that it brings an explanation that should have been given in a situation in which the fact that something is omitted is established into a situation in which the fact that something is omitted is not proven at all. If it is established that saṃghabheda is composed of α + β, but only α is written there, then the fact that β is omitted is established. Only then does the question arise, “Then why is β omitted here?” To answer this question, Fujimoto’s explanation that “β, which is an obvious thing that can be omitted, was omitted in order to focus on α,” makes sense.
However, the situation in the passage under discussion is completely different. It has not been established at all that saṃghabheda is composed of α + β. The phrase “there are two kinds of saṃghabheda” should be understood as it is: “there are two kinds of saṃghabheda.”
Fujimoto’s crtique consists of a piling up of a series of such arguments. It will take some time to find the means to publish my full rebuttal, but the author promises to make the full text public in due course.
