Esoteric Buddhism was systematized in the Maha vairocana-sutra and the Diamond Peak Sutra; ad both became the two principal scriptures of Chinese and Japanese Esoteric Buddism. Some scholars believe that both were composed in Nalanda in the latter half 7 century A.D
The Buddhism based on these two Tantric scriptures is generally called Mantra-yana by some scholars, fom which all other offshoots, such as Vaajayana, kalacakra-yana, Sahaja-yana, ect. Arose in later times, and which has constituted the framework of Chinese and Japanese Esoteric Buddhism. These two scriptures , althouht they are called sutras in the Sanskrit version , are definitely classified as Tantas ( Tibetan: rgyud ) by Tibetans ,because these two sutras have distinctivey Tantric features.