The Exoteric Teaching (Kengyo) and the Esoteric Teaching (Mikkyo)
The founder of Japanese Shingon Tradition, Kobo Daishi (Kukai), divided the whole of the Buddhadharma into two types : the Exoteric Teaching (Kengyo) and the Esoteric Teaching (Mikkyo). According to Kobo Daishi, it is only the Shingon Tradition which is the Esoteric Teaching, while all of the rest of the Buddhadharma are the Exoteric Teachings.
The Exoteric Teachings were all taught by the Nirmanakaya Buddha, the historic Buddha Sakyamuni. These Exoteric Teachings were modified in some ways when Sakyamuni taught the common people depending on their understanding skills. Furthermore, these teachings contained illustrative stories to hold the attention of his listeners. Stories which were not absolutely true. Such teachings are termed "Upaya teachings" (hoben-gyo) or "teachings which employ expedient means" to get their point across. These stories were devices to raise the spiritual consciousness of his listeners but were not teachings which contained the full presentation of the absolute level of Truth. Kobo Daishi commented that it would take the devotee a very long time to reach the state of Buddhahood if he were to cultivate his religious practices solely on the basis of the Exoteric Teaching truths.
The Esoteric Teachings, on the other hand, were preached by the dharmakaya Buddha, the Tathagata Mahavairocana. Mahavairocana understood the real aspects of the existence of all things in the universe, and through this enlightenment experience he came to possess, in perfect measure, all of the qualities of perfection. He then directly presented the full content of his enlightenment experience in the scriptures of the Shingon Tradition. He did not employ any "teaching devices" or ?expedient means? in this full presentation of the Truth. There was no consideration for the spiritual capacities or the intellectual facilities of his hearers. This was a presentation of the Truth with no admixture of anything less than the absolute level of Truth. Therefore, if the devotee cultivates his religious practice based on the directions given in the scriptures of the Shingon canon, he will attain to the unsurpassed state of Buddhahood in the shortest amount of time possible. It is for this reason then that the Esoteric Teachings were considered by Kobo Daishi to be the highest of the teachings contained within the Buddhadharma.
At the foundation of true religious belief lies doctrinal teachings and ritual practices to put those teachings into effect every day. Shingon Buddhism in particular is formed by the two pillars of doctrine and practice established by Kobo Daishi. Shingon Buddhism, teaches a profound doctrine and the right practices for human development. Therefore it must be understood that Shingon Esoteric Buddhism does not present itself simply as a religion of practical benefits, but is also a religion that recommends proper human development through right teachings.
The ultimate objective of the teachings of Shingon Buddhism is "to excel in skillful means," as explained in the Mahavairocana Sutra. The manner by which we pursue our lives, the way in which we relate to people, in other words, our own actions in life are to be regarded with utmost importance.
In one sense this is a religion that takes as its ideal what is spoken of as "personally becoming a buddha" as a result of correct practice, that is, becoming a perfect buddha in one's own body, the "perfect body of the Buddha" that is spoken of in the Kongocho-kyo. The teaching of Shingon Buddhism is based on the belief in these two pillars, and it allows each one of us to live fully the life we treasure as our one and only life safeguarded, as it was explained earlier, by the vows and protective powers of many buddhas.
