The Cheng weishi lun (=CWSL; T.1585), purporting to be a composite commentary on Vasubandhu's Trimsika Vijnaptimatratasiddhi, is a translation-compilation by Xuanzang (600-664 CE). with the assistance of his pupil Kuiji (632-682 CE). Xuanzang's main mission in this endeavour appears to be twofold: (i) the establishment and elucidation of the thesis of vijnaptimatra, and this predominantly on the basis of Dharmapala-Silabhadra's expositions; (ii) the harmonization of the earlier yogacara doctrinal interpretations, and in so doing also the definitive establishment of the superiority of the Mahayana bodhisattva ideal. The CWSL may be said to be one of the most precious gems in the whole of the Chinese Tripitaka. In the preface to his Shuji, Kuiji eulogizes the CWSL thus: This treatise purifies true cognition. Its expositions include the provisional as well as the ultimate teachings, going far beyond the early teachings of the historical Buddha. Its doctrines penetrate into the subtlest. They catch hold of the Prajnaparamita tenets and ride on their colourful brilliance. The treatise summarizes the essential teachings of the sutras, seeking out their hidden teachings and assimilating their purposes. It further incorporates the best of all the sastras, gathering up the most wonderful. The CWSL is a compilation containing the ten individual commentaries on Vasubandhu's Trimsika by 1. Dharmapala; 2. Gunamati; 3. Sthiramati; 4. Bandhusri; 5. Nanda; 6. Suddhacandra; 7. Citrabhanu; 8. Visesamitra; 9. Jinaputra and 10. Jnanacandra which are herewith collected together and translated in detail in a single text.