He was born on the 15th day of the 6th month in 774, in the town of Byobugaura in Sanuki Province on the Island of Shikoku (the present day town of Zentsuji in Kagawa Prefecture). I lis father Saeki Yoshimichikyo was a local provin cial governor, while his mother Tamayori Gozen was of the Ato clan. A legend has it that his mother became pregnant after she had a dream of a sagely Indian entering her abdomen.
As a child he was called Mao. At fifteen he went to the capital with his uncle Ato Otari and entered the University there at eighteen. At the time, the national university was designed for pro ducing government officials and its curriculum was based on the traditional Chinese Confucian educational system. 'I'his bureaucratically ori ented system may not have suited someone such as Kukai, whose concerns were for relieving the sufferings and anxieties of his fellow beings. While in the capital, he happened to receive the excellent teachings of a reputable Buddhist monk from lwabuchi named Gonso, as well as ritual instructions for engaging in an esoteric Buddhist practice devoted to a deity known as Kokuzo. It was apparently his experience with this contemplative practice that fired his deep interest in Buddhism.
Then in 793, when he was twenty, he decided to enter the priesthood. He took the tonsure under Gonso at Makinosan temple in Izumi (the temple is today known as Sefukuji in Izumi City, Osaka Prefecture), and changed his name to Kyokai only to change it again later to Nyoku. He took the name Kukai on the occasion of his full ordination ceremony at the Todaiji temple in Nara.
When he was twenty-four he composed in the form of a dramatic novel the essay Indications of the Three Teachings (Sango shiiki) in order to explain to those who opposed his decision his reason for entering the Buddhist priesthood. His early life as a monk was spent studying all kinds of Buddhist scriptures under Gonso at the Daianji temple in Nara. Apparently,however, he was not fully satisfied with his studies, and tradition says that he went to the hall of the Great Buddha at Todaiii temple where he prayed with utmost earnesty: "In seeking the essence of the Buddhist way I studied teachings of the various paths within the tradition and delved deeply into myriad scriptures. Yet my mind was still not ful filled. So it was that I beseeched with all my heart to the enlightened Buddhas in all directions and in the past, present and future, that the essence of the ultimate truth of non-duality be re vealed to me. " It is said that as a result of his prayer he was able to discover inside a small stupa at Kumedera temple in Yamato the scrip ture known as the Dainichi-kyo. He was corn pletely overjoyed by finding this text, in which are such passages as the following: "To be enlightened is simply to understand fully the true nature of your own mind. Understanding fully the true nature of your own mind is equal to understanding everything. " The text is known for conveying the realm of enlightenment in most direct terms, combining careful attention to both theo retical and practical aspects of the path to the attainment of the highest sprititual goal of Buddhahood.
It seems that this was what Kukai had been seek ing after, for it was in this very text that he found the entrance to the path of enlightenment. He studied the text intensively, but it was difficult to understand. There were passages in Sanskrit and other sections that no one in Nara could explain adequately to him. And so it was that he became desirous of travelling to China, where the text had been translated from the original Sanskrit into the classical Chinese form common in Japan. In 804 he received official permission to study abroad whereupon he left the ranks of his mentor Gonso.
The boat on which Kukai rode to China was part of an official mission including the Japanese ambassador. On another boat in the mission rode the monk Saicho, founder of the Tendai school, who was also going in order to study Buddhism. On the 6th day of the 7th month, the ship departed from the harbor of Tanoura in Kyushu, and arrived on the Chinese coast at Fuchou on the 10th day of the 8th month. By the 12th month Kukai had entered the capital of Chang-an and been admitted as a student of the master of esoteric Buddhism I lui-kuo, who is today recognized as the seventh in the Shingon lineage of eight patriarchs. During the next eight months, Hui-kuo instructed Kukai in all the essentials of esoteric Buddhist theory and practice and gave him the religious name Henjo Kongo meaning " universally illuminating adamantine one (vajra)." Ile then selected this young, thirty-two year old Japanese monk as his successor over his hundreds of Chinese disciples. This is why Kukai is considered to be the eighth patriarch. Huikuo's choice of Kukai suggests the degree to which he was seen as possessing superior virtues for the religious life.
In the same twelfth month, however, Hui- kuo conveyed to Kukai these instructions: "You have received all that I have to transmit. Return now to your homeland and promulgate this teaching in order to increase the happiness of the people and promote peace in the land. " Shortly thereafter the master passed away. Holding back his sadness, Kukai returned to Japan, arriving safely in 806. The following year he went to the capital in Kyoto bringing with him the vast collections of texts he had accumulated in China. After paying his respects to the Emperor Ileijo, he received permission to instruct others in this new teaching and proceeded to lecture on the Dainichi-kyo at Kumedera temple in Nara, the place where years earlier he had received inspiration from the same text. In all, he created quite a sensation both within the Imperial Court circles and elsewhere.
After his first lectures he moved to Makinosan temple south of the capital, and then was later or dered by the Court to reside at Jingoji temple at Mt. Takao near Kyoto. He eventually founded Koyasan (in 817) and in 823 Emperor Saga entrusted him with the Toji temple within the capi tal as a place for the exclusive training of Shingon priests. Kukai's teaching efforts were understood to be aimed ultimately at the promotion of peace and security throughout the land. Once having this base at Toji in Kyoto, Kukai's new form of Buddhism began to penetrate deeply into the lives of people in the capital as well as in the provinces.
But Kukai's activity was not limited merely to the promulgation of Buddhist practice of his Shingon school. Ile was also engaged in such efforts as the founding of the first private school in Japan devoted to the education of the general populace. Traditions about him also include reports of his expertise in fields such as, calligraphy, painting and sculpture, as inventing the Japanese syllabary, discovering hot springs, instructing people in the use of coal, and with constructing dams, bridges and roads. In short he made a remarkable impact on the development of Japanese civilization in general, and it is no wonder that he has at times been referred to as a veritable "mother of Japanese culture."
Having made such contributions to his society, in the first month of 835 he performed a week long service for the peace and prosperity of Japan inside the Imperial palace. Then, in the second month he announced his departure from Kyoto and headed for the last time to Koyasan. Since returning from China in 806, he had spent his time divided between his activities around the capital and the task of constructing a monastic center atop the distant mountain of Koya. Upon arriving in Koyasan for his last time, he assumed a fast which included no intake of grains, and diligently practiced seated meditation. On the 15th day of the 3rd month he called his disciples together in order to announce that on the 21st day he would pass away. In addition to this prediction, he conferred upon his disciples a list of twenty- five injunctions that must be strictly maintained by all followers of his school. Then, after ritually purifying his body and donning clean robes, he went to a predetermined room where he assumed the full cross-legged posture. Placing his hands in the ritual gesture symbolizing the deity Dainichi Nyorai (the personifica tion of ultimate truth) and intoning the sacred formula of the same, he entered the contemplative absorption of Maitreya (known as the Buddha of the millenia). He remained in this state for seven days until the 21st of the third month in 835, when he entered the eternal adamantine concentration just as he had predicted. He was sixty-two years old. In 919, fifty eight years later, the Emperor Daigo bestowed upon him the posthumous honorific title Kobo Daishi.