Shingon ( 真言宗) is one of the major schools of Japanese Buddhism, and the most important school of Vajrayana Buddhism outside of the Himalayan region. The word Shingon is a Japanese pronunciation of the Chinese term Zhen Yan meaning "True Word", which itself is a representation of the Sanskrit word for mantra. Shingon arose in Japan's Heian period (794-1185) when the monk Kukai went to China in 804 where he studied the tantra and returned armed with many texts and art works, and developed his own synthesis of esoteric practice and doctrine, centred on the cosmic Buddha Vairocana.
The teachings of Shingon are based on the Mahavairocana Sutra and the Vajrasekhara Sutra. Vajrayana Buddhism is concerned with the ritual and meditative practices leading to enlightenment. According to Shingon, enlightenment is not a distant, foreign reality that can take eons to approach but our birth-right, a real possibility within this very life. With the help of a genuine teacher and through properly training the body, speech, and mind, we can reclaim and liberate this enlightened capacity for the benefit of ourselves and others.
In Shingon the Buddha Vairocana is held to be within all things. The goal of Shingon is the realization that one's nature was identical with Vairocana, a goal that is achieved through meditation and ritual practices. This realization depends on receiving the secret doctrine of Shingon, transmitted orally to initiates by the school's masters. Body, speech, and mind all participate in the process: the body through devotional gestures (mudra) and the use of ritual instruments, speech through sacred formulas (mantra), and mind through meditation.
One thing that sets Shingon apart from the other surviving schools of esoteric Buddhism in Tibet is the use of calligraphy, instead of pictorial representations, to represent Buddha figures in their mandalas. An ancient Indian script known as Siddham is used to write mantras and draw mandalas.
Kukai also systematised and catergorised the teachings he inherited. However he admitted only one class of esoteric text. He wrote at length on the difference between exoteric (Mahayana) and esoteric (Vajrayana) Buddhism, developing a sophisticated jargon which can make understanding the Vajrayana difficult at first. The differences between exoteric and esoteric can be summarised as:
- Esoteric teachings are preached by the Dharmakaya Buddha which Kukai identifies with Mahavairocana. Exoteric teachings are preached by the Nirmanakaya Buddha, also known as Gautama Buddha, or one of the Sambhoghakaya Buddhas.
- Exoteric Buddhism holds that the state of Buddhahood is ineffable, and that nothing can be said of it. Esoteric Buddhism holds that it is not ineffable, and that it is communicated via esoteric rituals which involve the use of mantras, mudras, and mandalas.
- Kukai held that exoteric doctrines were merely provisional, skillful means on the part of the Buddhas to help beings according to their capacity to understand the Truth. The esoteric doctrines by comparison are the Truth itself, and are a direct communication of the "inner experience of the Dharamakaya's enlightenment".
- Exoteric schools, in early Heian Japan at least, held that Buddhahood required three incalculable aeons of practice to achieve, whereas esoteric Buddhism holds that Buddhahood can be attained in this lifetime by anyone.
Kukai held, along with the Hua-yen (Jp. Kegon) school that all phenomena were 'letters' in a 'world-text'. Mantra, mudra, and mandala are special because they constitute the 'language' through which the Dharmakaya (i.e. Reality itself) communicates. Although portrayed through the use of anthropomorphic metaphors, Shingon does not see the Dharmakaya Buddha as a god, or creator. The Dharmakaya is in fact a symbol for the true nature of things which is impermanent and empty of any essence. The teachings were passed from Mahavairocana via a succession of mythic and historical patriarchs.
The essence of Shingon Vajrayana practice is to experience Reality by reproducing the communication of the Dharmakaya through the meditative ritual use of mantra, mudra and visualization of mandala. In order to accurately reproduce the communication it is necessary to be initiated into the practice by a qualified teacher.
Esoteric Buddhism is also practised, although to a lesser extent, in the Tendai School founded at around the same time as the Shingon School in the early 9th century (Heian period).
Just as the Tibetans incorporated Bön elements into Buddhism, the Japanese incorporated aspects of their native Shintō religion. In particular the central Buddha figure of Mahavairocana (Jp. Dainichi), whose name means "Great Illuminating Sun", was identified with the sun goddess Amateratsu.