In Buddhism, words are recited as mantras (shingon) or incantations (jumon), and words are written down as prayers and deposited within the womb-like interiors of Buddhist sculpture. In both cases these are important acts incorporating the wishes of a worshiper or a Buddhist sculptor. In short, their aim is to link these people with the Buddhist icons. Esoteric Buddhist language often accompanies secret rites and frequently forms a portion of Esoteric Buddhist scripture. However, when recited in the context of Esoteric Buddhist ritual procedures to secure this-worldly benefit, this language arouses mysterious power capable of influencing the actions of gods or humans and natural forces as well. Furthermore, its effects are innumerable. Moreover, its aim may alter the fate of nations or the hearts and minds of human beings. The words of Esoteric Buddhist language are often condensations of many linguistic sounds, and these words have a powerful impact. In addition, they have the astonishing capacity to eliminate catastrophes and alter situations that seem impossible for humans. Likewise, when a mantra is recited during spiritual training involving fire and water, the efficacy of the power engendered by the words can be greatly enhanced. The unseen, ineffable force inherent in fire and water incites a level of power that cannot be anticipated. This is similar to the effect and function of a secret Buddha (hibutsu) when it is revealed. It is extremely difficult to grasp the power of the true essence latent within incantations such as mantra and dhāraṇī, but the existence of the power of these words as seen through their utterance and meaning is certain. In any case, it is undeniably true that the power of Esoteric Buddhist language undoubtedly forms the core in responding to the aim of attaining benefit in this world. In addition, it is not only the case with spoken words ladled over the exterior of Buddhist sculpture, but it is also the case with those written within the sculpture (inscriptions in the womb-like interior, the tainaimei), whose efficacy varies as one type differs from the other. In any case, the power of esoteric words undoubtedly forms the core in response to the aim of attaining this-worldly benefit. As inscriptions may have been concealed within the womb-like interior of a statue for decades, the instant the enclosure is opened and they are revealed, the efficacy of the words is instantaneously enhanced and continues to benefit worshippers. Thus, we consider the power of this kind of language from various perspectives. Particularly in the case of Buddhist sculpture, the mantra of Nyoirin Kannon is an example of such language, becoming first a stylized staff-like nyoi and eventually manifesting itself as a jewel, thus giving birth to the physical embodiment of its operation and providing proof of the theory that the existence of life is due to human death. This theory is that of the nyoi, or, in other words, Buddha relics.
Here the Shingon practitioner seeks in the Buddha relic the basis for the generation of Esoteric Buddhist language and considers the mechanism that brings about its physical form.
