From the traditional point of view of the Indo-Tibetan form of Mahayana Buddhism, Buddha himself taught four major tenet systems (grub-mtha’, Skt. siddhanta) to suit the dispositions and capacities of different disciples. Hinayana had eighteen schools and within one of them, Sarvastivada (Thams-cad yod-par smra-ba), two of the tenet systems emerged: Vaibhashika (Bye-brag smra-ba) and Sautrantika (mDo-sde-pa). The other two appeared within Mahayana: Chittamatra (Sems-tsam-pa) and Madhyamaka (dBu-ma-pa). Other names for Chittamatra are Yogachara (rNal-‘byor spyod-pa) and Vijnanavada (rNam-par shes-pa tsam-du smra-ba). Although other Hinayana schools, for instance Theravada (gNas-brtan smra-ba, Skt. Sthaviravada), have their own distinctive set of assertions, they are not counted among the tenet systems.
Various Tibetan masters have identified and named differently subdivisions within each of the four traditional Indian tenet systems. There is little evidence, however, that these subdivisions existed in India. The most important of them is the subdivision of Madhyamaka into Svatantrika-Madhyamaka (dBu-ma rang-rgyud-pa) and Prasangika-Madhyamaka (dBu-ma thal-‘gyur-pa). Also significant, according to Gelug, is the division within Svatantrika-Madhyamaka between Yogachara-Svatantrika (rNal-byor spyod-pa’i dbu-ma rang-rgyud-pa) and Sautrantika-Svatantrika (mDo-sde-pa’i dbu-ma rang-rgyud-pa).
From a historical point of view, various Indian masters specialized in and taught these systems as separate Buddhist traditions. The fact that some of them were transmitted to China as individual schools corroborates this fact.
In the Indian Mahayana Buddhist monasteries, such as Nalanda, monks studied all four traditions. The Tibetans have followed this custom, with different subjects and texts taught from the points of view of different tenet systems.
The Four Major Tenet Systems
Tibetans study Vaibhashika in the context of special topics of knowledge (chos mgon-pa, Skt. abhidharma), specifically the lower system of abhidharma (mngon-pa ‘og-ma), as formulated by Vasubandhu (dByigs-gnyen).
- Vasubandhu wrote A Treasure House of Special Topics of Knowledge (Chos mngon-pa’i mdzod, Skt. Abhidharma-kosha).
They study Sautrantika in the context of valid cognition (tshad-ma, Skt. pramana), as formulated by Dignaga (Phyogs-kyi glangs-pa) and Dharmakirti (Chos-kyi grags-pa).
- Dignaga wrote A Compendium of Validly Cognizing Minds (Tshad-ma kun-las btus-pa, Skt. Pramana-samuccaya).
- Dharmakirti wrote A Commentary to (Dignaga’s “Compendium of) Validly Cognizing Minds” (Tshad-ma rnam-‘grel, Skt. Pramana-varttika).
Tibetans study Chittamatra in the context of the higher system of abhidharma (mngon-pa gong-ma), as formulated by Asanga (Thogs-med). They supplement this with further aspects of valid cognition in Dharmakirti’s Commentary to (Dignaga’s “Compendium of) Validly Cognizing Minds.”
- Asanga wrote An Anthology of Special Topics of Knowledge (mNgon-pa chos kun-las btus-pa, Skt. Abhidharma-samuccaya).
They study Madhyamaka in general as presented in the works of Nagarjuna (Klu-sgrub).
- Nagarjuna wrote Root Verses on the Middle Way, Called Discriminating Awareness (dBu-ma rtsa-ba shes-rab, Skt. Prajna-nama-mulamadhyamaka-karika), and many other texts.
The Two Divisions of Madhyamaka
Tibetans study Svatantrika-Madhyamaka in general in the context of far-reaching discriminating awareness (sher-phyin, Skt. prajnaparamita, perfection of wisdom), as formulated by Maitreya (Byams-pa).
- Maitreya wrote A Filigree of Realizations (mNgon-rtogs rgyan, Skt. Abhisamaya-alamkara).
They study Prasangika-Madhyamaka through the works of Chandrakirti (Zla-ba grags-pa), Aryadeva (‘Phags-pa lha), Shantideva (Zhi-ba lha), and Buddhapalita (Sang-rgyas bskyangs).
- Chandrakirti wrote A Supplement to (Nagarjuna’s “Root Verses on) the Middle Way” (dBu-ma-la ‘jug-pa, Skt. Madhyamaka-avatara).
- Aryadeva wrote Four Hundred Verse Treatise (bZhi-brgya-pa, Skt. Catuhshataka).
- Shantideva wrote Engaging in Bodhisattva Behavior (sPyod-‘jug, Bodhisattvacarya-avatara).
- Buddhapalita wrote A Commentary to (Nagarjuna’s) “Root Verses on the Middle Way, Called Discriminating Awareness” (rTsa-ba shes-rab-gyi ‘grel-ba, Skt. Mulamadhyamaka-vrtti).
The Two Divisions of Svatantrika-Madhyamaka
Tibetans study Yogachara-Svatantrika through the works of Shantarakshita (Zhi-ba ‘tsho), who first brought Indian Buddhism to Tibet, and his disciples Kamalashila (Ka-ma-la shi-la), who defeated the Chinese monk Hoshang at the Samyey debate, and Haribhadra (Seng-ge bzang-po).
- Shantarakshita wrote A Filigree of the Middle Way (dBu-ma rgyan, Skt. Madhyamaka-alamkara) and A Compendium of Principles (De-kho-na-nyid-kyi bsdud-pa, Skt. Tattva-samgraha).
- Kamalashila wrote Stages of Meditation (sGom-rim, Skt. Bhavanakrama) and Illumination for the Middle Way (dBu-ma snang-ba, Skt. Madhyamaka-aloka).
- Haribhadra wrote A Commentary (to Maitreya’s “Filigree of Realizations”), Clarifying the Meaning (‘Grel-ba don-gsal, Skt. Sphutartha).
They study Sautrantika-Svatantrika through the works of Bhavaviveka (Bhavya) (Legs-ldan ‘ byed).
- Bhavaviveka wrote Heart of the Middle Way (dBu-ma’i snying-po, Skt. Madhyamaka-hrdaya) and its auto-commentary Blaze of Reasoning (rTog-ge ‘bar-ba, Skt. Tarkajvala).