Ñāṇa wrote:The Abhidharmakośa is the root verses. The Abhidharmakośabhāsya is the commentary paragraphs interspersed between the root verses. The Tibetans consider the Abhidharmakośa root verses to be Sarvāstivāda and the Abhidharmakośabhāsya to be Sautrāntika.
All the best,
Oh I never looked at it that way - that explains the rather ambivalent naming.
In any case I also compared now and French and English are the same after all - always thought the bashya to contain an incomplete rendering of the Kosha due to the sometimes rather fragmentary nature of the contained stanzas. Thx.
The way the Chinese explain it, is that Vasubandhu wrote the Kosa verses and presented them to Samghabhadra. They were written in a manner that first appeared to support the Vaibhasika position. Then, impressed, Samghabhadra asked for the bhasya commentary on the kosa verses. Vasubandhu obliged, but his commentary was critical of the Vaibhasika position. This really irked old Samghabhadra, who used the same kosa verses to first write an orthodox Vaibhasika commentary called the Nyayanusara, and then the Xianzong Lun (Skt name eludes me for the moment), both of which are quite a bit larger than the kosa-bhasya of Vasubandhu. (Both are also preserved in Chinese alone, from Xuanzang's translations.)
To the Chinese, the Kosa verses are thus kind of general Abhidharma type, hard to say that they are either Vaibhasika or Sautrantika, or otherwise. Vasubandhu's bhasya commentary is not considered strictly Sautrantika, because it has some positions that are more like the Vaibhasikas still. eg. acceptance of both the ayatanas and dhatus as real existents, the Sauntrantikas only accept the dhatus, and the Sarvastivadins accept ayatana, dhatu as well as skandha. This is just one example. But the Nyananusara and Xianzong are strict orthodox Vaibhasika of the time. There is some debate about how much Samghabhadra extends the Vibhasa to make his own neo-Vaibhasika, but my understanding is that he is pretty true to the orthodox position (pingyue) of the Vibhasa. I don't think that even Samghabhadra calls Vasubandhu a Sautrantika, but the "sastra author". However, in Samghabhadra's works, and obviously also the Vibhasa itself, we see further evidence on the position of the early Sautrantikas and Darstantikas, such as Srilata, Kumaralata, etc. There are no other sources for these outside the Chinese.
Although I don't know much about the Tibetan position on all of this, from what little I do know, I often feel that the Tibetans are quite hindered by not having the Vibhasa itself, or the rest of the seven standard Sarvastivada Abhidharma Sastras, or some of the other sastras. So, it seems to me that they have to rely heavily on the Kosa as one of their main sources for the Sarvastivada position. From the Chinese point of view, this is completely unnecessary, as they still have all the main earlier sastras intact, including multiple versions in some cases (eg. the Vibhasa itself, the Pancavastuka, etc.)
My little understanding of this is all from Bhante Prof Dhammajoti's classes. So, if you want the real juice, his books are definitely the ticket!