The term utsutra, referring to a deviation from sutra, is used only five times in the Abhidharmakosabhasya (hereafter AKBh) in the following order: (1) AKBh 13.25 ad AK I, 20ab, (2) AKBh 136.17 ad AK III, 25a-28a, (3) AKBh 215.17, 18 ad AK IV, 31a-c, (4) AKBh 333.3 ad AK VI, 3a-d, (5) AKBh 464.10 (cf. s. v. utsutra in the Index to the AKBh). In cases (1), (3), (4), and (5), Vasubandhu himself points out that the opponent's arguments deviate from sutra, while in case (2) the Sautrantikas do so. The sutra referenced in the latter case (2) is given the title of the Pratityasamutpadasutra by Sanghabhadra. Vasubandhu makes no mention of a sutra-title except the Mahanamasutra in case (3).
All sutra-phrases quoted in cases (1) (2) (3) (5), including the still unidentified case (4), are transmitted agama-phrases from the Chinese Samyukta-Agama. Furthermore, the method of Pratikapatha in case (2) is not accompanied with the ordinary expression for a sutra-quotation―sutra uktam―, and takes the tactic of explaining the reason as being that the full explanation is given in the sutra [in itself] in another way (sutra 'nyatha nirdesat). We find such stock phrases representing the standpoint of the Vaibhasikas only in the context of cases (2) and (4), i. e. abhiprayikah sutre, laksaniko 'bhidharmahh and/or abhiprayikah sutresu nirdeso, laksanikas tv abhidharme. In this paper, I would like to elucidate the specific nature of the sutra here, esp. in the case of (2).