The Mahayanist scriptures are so voluminous that not even the clergy were expected to master any considerable part of them.[128] Indeed they make no claim to be a connected whole. The theory was rather that there were many vehicles plying on the road to salvation and many guide books. No traveller thought of taking the whole library but only a few volumes which suited him. Most of the Chinese and Japanese sects avowedly base themselves upon three sutras, selected according to the taste of each school from the hundreds quoted in catalogues. Thus the T'ien-t'ai sect has for its scriptures the Lotus, the Nirvâṇa-sûtra and the Prajñâ-pâramitâ, while the Shin-shu sect admits only the three Amidist sutras. The following are the names of some of the principal Mahayanist scriptures. Comparatively few of them have been published in Europe and some exist only in Chinese or Japanese translations. 1. Prajñâ-pâramitâ or transcendental knowledge[129] is a generic name given to a whole literature consisting of treatises on the doctrine of śûnyatâ, which vary greatly in length. They are classed as sutras, being described as discourses delivered by the Buddha on the Vulture Peak. At least ten are known, besides excerpts which are sometimes described as substantive works. The great collection translated into Chinese by Hsüan Chuang is said to consist of 200,000 verses and to comprise sixteen different sutras.[130] The earliest translation of one of these treatises into Chinese (Nanjio, 5) was made about 170 A.D. and everything indicates that portions of the Prajñâ-pâramitâ are among the earliest Mahayanist works and date from about the first century of our era. Prajñâ not only means knowledge of the absolute truth, that is to say of śûnyatâ or the void, but is regarded as an ontological principle synonymous with Bodhi and Dharma-kâya. Thus Buddhas not only possess this knowledge in the ordinary sense but they _are_ the knowledge manifest in human form, and Prajñâ is often personified as a goddess. All these works lay great stress on the doctrine of śûnyatâ, and the non-existence of the world of experience. The longest recension is said to contain a polemic against the Hinayana. The Diamond Cutter is one of the best known of these transcendental treatises and the two short works called Heart of the Prajñâ-pâramitâ, which are widely read in Japan, appear to be brief abstracts of the essence of this teaching.