Chinese Esoteric Buddhism in the context of "Deity yoga"

East Asian Buddhism or East Asian Mahayana is a collective term for the schools of Mahāyāna Buddhism which developed across East Asia and which rely on the Chinese Buddhist canon. These include the various forms of Chinese, Japanese, Korean, and Vietnamese Buddhism. East Asian Buddhists constitute the numerically largest body of Buddhist traditions in the world, numbering over half of the world's Buddhists.

East Asian forms of Buddhism all derive from the sinicized Buddhist schools which developed during the Han dynasty and the Song dynasty, and therefore are influenced by Chinese culture and philosophy. The spread of Buddhism to East Asia was aided by the trade networks of the Silk Road and the missionary work of generations of Indian and Asian Buddhists. Some of the most influential East Asian traditions include Chan (Zen), Nichiren Buddhism, Pure Land, Huayan, Tiantai, and Chinese Esoteric Buddhism. These schools developed new, uniquely East Asian interpretations of Buddhist texts and focused on the study of Mahayana sutras. According to Paul Williams, this emphasis on the study of the sutras contrasts with the Tibetan Buddhist attitude which sees the sutras as too difficult unless approached through the study of philosophical treatises (shastras).

Chinese Buddhism or Han Buddhism (traditional Chinese: 漢傳佛教; simplified Chinese: 汉传佛教) is a Chinese form of Mahayana Buddhism and is the largest institutionalized religion in mainland China. As of 2017, there are an estimated 185 to 250 million Chinese Buddhists in the People's Republic of China. It is also a major religion in Taiwan, Singapore, and Malaysia, as well as among the Chinese diaspora.

Buddhism was first introduced to China during the Han dynasty (206 BCE – 220 CE). It was promoted by multiple emperors, especially during the Tang dynasty (618–907 CE), which helped it spread across the country. The translation of a large body of Indian Buddhist scriptures into Chinese and the inclusion of these translations (along with Taoist and Confucian works) into a Chinese Buddhist canon had far-reaching implications for the dissemination of Buddhism throughout the East Asian cultural sphere, including Korea, Japan, and Vietnam. Chinese Buddhism also developed various unique traditions of Buddhist thought and practice, including Tiantai, Huayan, Chan, Pure Land, and Esoteric Buddhism.

A vajrācārya (vajra + acharya, Tibetan: རྡོ་རྗེ་སློབ་དཔོན་, dorje lopön, Wyl. rdo rje slob dpon, Chinese: 金剛阿闍梨, pinyin: jīngāng āshélì; rōmanji: kongō ajari) (alternatively, Chinese: 金剛上師, pinyin: jīngāng shàngshī) is a Vajrayana Buddhist master, guru or priest. It is a general term for a tantric master in Vajrayana and Mahayana Buddhist traditions, including Tibetan Buddhism, Chinese Esoteric Buddhism, Chan Buddhism, Shingon, Bhutanese Buddhism, Newar Buddhism.

A ḍākinī (Sanskrit: डाकिनी; Tibetan: མཁའ་འགྲོ་མ་, Wylie: mkha' 'gro ma, THL: khandroma; Mongolian: хандарма; Chinese: 空行母; pinyin: kōngxíngmǔ; lit. 'sky-going mother'; alternatively 荼枳尼, pinyin: túzhǐní; 荼吉尼, pinyin: tújíní; or 吒枳尼, pinyin: zhāzhǐní; Japanese: 荼枳尼 / 吒枳尼 / 荼吉尼, dakini) is a type of goddess in Hinduism and Buddhism.

The concept of the ḍākinī somewhat differs depending on the context and the tradition. For example, in earlier Hindu texts and East Asian esoteric Buddhism, the term denotes a race of demonesses who ate the flesh and/or vital essence of humans. In Hindu Tantric literature, Ḍākinī is the name of a goddess often associated with one of the six chakras or the seven fundamental elements (dhātu) of the human body. In Nepalese and Tibetan Buddhism, meanwhile, 'ḍākinī' (also wisdom ḍākinī) can refer to both what can be best described as fierce-looking female embodiments of enlightened energy, and to human women with a certain amount of spiritual development, both of whom can help Tantric initiates in attaining enlightenment.

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.

Yixing (Chinese: 一行; pinyin: Yīxíng; Wade–Giles: I-Hsing, 683–727) was a Buddhist monk of the Tang dynasty, recognized for his accomplishments as an astronomer, a reformer of the calendar system, a specialist in the Yijing (易經), and a distinguished Buddhist figure with expertise in Esoteric Buddhism.

In the realm of secular affairs, Yixing gained prominence for his reforms to the imperial calendar and his construction of a celestial globe featuring a liquid-driven escapement, the first in a long tradition of Chinese astronomical clockworks. Within Buddhist circles, he is particularly remembered for his contributions to the translation of the Mahāvairocana-sūtra and for authoring the authoritative commentary on that scripture, the Darijing shu 大日經疏 (T 1796). Due to his significant activities in both religious and secular spheres, a legendary portrayal of Yixing as a master astrologer and practitioner of astral magic developed during the late Tang period, leading to the attribution of several astrological works to him.

A yidam or iṣṭadevatā is a meditational deity that serves as a focus for meditation and spiritual practice, said to be manifestations of Buddhahood or enlightened mind. Yidams are an integral part of Vajrayana, including Tibetan Buddhism, Chinese Esoteric Buddhism and Shingon, which emphasize the use of esoteric practices and rituals to attain enlightenment more swiftly. The yidam is one of the three roots of the inner refuge formula and is also the key element of deity yoga. Yidam is sometimes translated by the term "tutelary deity".

A yidam is considered to be a manifestation of enlightened qualities and a means to connect with specific aspects of the enlightened mind. The yidam is visualized during meditation in intricate detail, with the aim of internalizing its qualities and attributes. This practice is intended to facilitate the practitioner's transformation and realization of their own innate enlightened nature. It is believed to help purify the mind, accumulate positive karma, and ultimately lead to the realization of emptiness and the nature of reality.