Shingon (真言宗, Shingon-shū; "True Word/Mantra School") is one of the major schools of Buddhism in Japan and one of the few surviving Vajrayana lineages in East Asian Buddhism. It is a form of Japanese Esoteric Buddhism and is sometimes called "Tōmitsu" (東密 lit. "Esoteric [Buddhism] of Tō-ji"). The word shingon is the Japanese reading of the Chinese word 真言 (zhēnyán), which is the translation of the Sanskrit word mantra.
The Zhenyan lineage was founded in China (c. 7th–8th centuries) by Indian vajrācāryas (esoteric masters) like Śubhakarasiṃha, Vajrabodhi and Amoghavajra. These esoteric teachings would later flourish in Japan under the auspices of a Buddhist monk named Kūkai (空海, 774–835), who traveled to Tang China and received these esoteric transmissions from a Chinese master named Huiguo (746–805). Kūkai established his tradition at Mount Kōya (in Wakayama Prefecture), which remains the central pilgrimage center of Shingon Buddhism.