Vajrayana is sometimes known as Tantric Buddhism in the west . Although there is historical evidence for Vajrayana Buddhism in Southeast Asia and elsewhere ( see History of Vajrayana below ) , today the Vajrayana exists primarily in the form of the two major sub-schools of Tibetan Buddhism and Esoteric Buddhism in Japan known as Shingon , with a handful of minor subschools utilising lesser amounts of esoteric or tantric materials .