Kūkai (空海; Japanese pronunciation: [kɯꜜː.kai], 27 July 774 – 22 April 835), born Saeki no Mao (佐伯 眞魚) posthumously called Kōbō Daishi (弘法 大師; [koː.boː daꜜi.ɕi], lit. 'the Grand Master Who Propagated the Dharma'), was a Japanese Buddhist monk, calligrapher, and poet who founded the esoteric Shingon school of Buddhism. He travelled to China, where he studied Tangmi (Chinese Vajrayana Buddhism) under the monk Huiguo. Upon returning to Japan, he founded Shingon—the Japanese branch of Vajrayana Buddhism. With the blessing of several Emperors, Kūkai was able to preach Shingon teachings and found Shingon temples. Like other influential monks, Kūkai oversaw public works and constructions. Mount Kōya was chosen by him as a holy site, and he spent his later years there until his death in 835 CE.
Because of his importance in Japanese Buddhism, Kūkai is associated with many stories and legends. One such legend attributes the invention of the kana syllabary to Kūkai, with which the Japanese language is written to this day (in combination with kanji), as well as the Iroha poem, which helped to standardise and popularise kana.
Shingon followers usually refer to Kūkai by the honorific title of Odaishi-sama (お大師様; "The Grand Master"), and the religious name of Henjō Kongō (遍照金剛; "Vajra Shining in All Directions").
Kūkai was born in 774 in the precinct of Zentsū-ji temple, in Sanuki province on the island of Shikoku. His family were members of the aristocratic Saeki family, a branch of the ancient Ōtomo clan. In modern scholarship, his first name is generally believed to be Mao ("True Fish"), although one source records his birth name as Tōtomono ("Precious One"). Kūkai was born in a period of important political changes with Emperor Kanmu (r. 781–806) seeking to consolidate his power and to extend his realm, taking measures which included moving the capital of Japan from Nara ultimately to Heian (modern-day Kyoto).
Little more is known about Kūkai's childhood. At the age of fifteen, he began to receive instruction in the Chinese classics under the guidance of his maternal uncle. During this time, the Saeki-Ōtomo clan suffered government persecution due to allegations that the clan chief, Ōtomo Yakamochi, was responsible for the assassination of his rival Fujiwara no Tanetsugu. The family fortunes had fallen by 791 when Kūkai journeyed to Nara, the capital at the time, to study at the government university, the Daigakuryō (大学寮). Graduates were typically chosen for prestigious positions as bureaucrats. Biographies of Kūkai suggest that he became disillusioned with his Confucian studies, but developed a strong interest in Buddhist studies instead.
Around the age of 22, Kūkai was introduced to Buddhist practice involving chanting the mantra of Kokūzō (Sanskrit: Ākāśagarbha), the bodhisattva of the void. During this period, Kūkai frequently sought out isolated mountain regions where he chanted the Ākāśagarbha mantra relentlessly. At age 24 he published his first major literary work, Sangō Shiiki, in which he quotes from an extensive list of sources, including the classics of Confucianism, Daoism, and Buddhism. The Nara temples, with their extensive libraries, possessed these texts.
During this period in Japanese history, the central government closely regulated Buddhism through the Sōgō (僧綱, 'Office of Priestly Affairs') and enforced its policies, based on the ritsuryō legal code. Ascetics and independent monks, like Kūkai, were frequently banned and lived outside the law, but still wandered the countryside or from temple to temple.
During this period of private Buddhist practice, Kūkai had a dream, in which a man appeared and told Kūkai that the Mahavairocana Tantra is the scripture which contained the doctrine Kūkai was seeking. Though Kūkai soon managed to obtain a copy of this sutra which had only recently become available in Japan, he immediately encountered difficulty. Much of the sutra was in untranslated Sanskrit written in the Siddhaṃ script. Kūkai found the translated portion of the sutra was very cryptic. Because Kūkai could find no one who could elucidate the text for him, he resolved to go to China to study the text there. Ryuichi Abe suggests that the Mahavairocana Tantra bridged the gap between his interest in the practice of religious exercises and the doctrinal knowledge acquired through his studies.
In 804, Kūkai took part in a government-sponsored expedition to China, led by Fujiwara no Kadanomaro, in order to learn more about the Mahavairocana Tantra. Scholars are unsure why Kūkai was selected to take part in an official mission to China, given his background as a private monk who was not sponsored by the state. Theories include family connections within the Saeki-Ōtomo clan, or connections through fellow clergy or a member of the Fujiwara clan.
The expedition included four ships, with Kūkai on the first ship, while another famous monk, Saichō was on the second ship. During a storm, the third ship turned back, while the fourth ship was lost at sea. Kūkai's ship arrived weeks later in the province of Fujian and its passengers were initially denied entry to the port while the ship was impounded. Kūkai, being literate in Chinese, wrote a letter to the governor of the province explaining their situation. The governor allowed the ship to dock, and the party was asked to proceed to the capital of Chang'an (present day Xi'an), the capital of the Tang dynasty.
After further delays, the Tang court granted Kūkai a place in Ximing Temple, where his study of Chinese Buddhism began in earnest. He also studied Sanskrit with the Gandharan pandit Prajñā (734–810?), who had been educated at the Indian Buddhist university at Nalanda.
It was in 805 that Kūkai finally met the monk Huiguo (746–805) the man who would initiate him into Chinese Esoteric Buddhism (Tangmi) at Chang'an's Qinglong Monastery (青龍寺). Huiguo came from an illustrious lineage of Buddhist masters, famed especially for translating Sanskrit texts into Chinese, including the Mahavairocana Tantra. Kūkai describes their first meeting:
Accompanied by Jiming, Tansheng, and several other Dharma masters from the Ximing monastery, I went to visit him [Huiguo] and was granted an audience. As soon as he saw me, the abbot smiled, and said with delight, "since learning of your arrival, I have waited anxiously. How excellent, how excellent that we have met today at last! My life is ending soon, and yet I have no more disciples to whom to transmit the Dharma. Prepare without delay the offerings of incense and flowers for your entry into the abhisheka mandala".
Huiguo immediately bestowed upon Kūkai the first level abhisheka (esoteric initiation). Whereas Kūkai had expected to spend 20 years studying in China, in a few short months he was to receive the final initiation, and become a master of the esoteric lineage. Huiguo was said to have described teaching Kūkai as like "pouring water from one vase into another". Huiguo died shortly afterwards, but not before instructing Kūkai to return to Japan and spread the esoteric teachings there, assuring him that other disciples would carry on his work in China.
Kūkai arrived back in Japan in 806 as the eighth Patriarch of Esoteric Buddhism, having learnt Sanskrit and its Siddhaṃ script, studied Indian Buddhism, as well as having studied the arts of Chinese calligraphy and poetry, all with recognized masters. He also arrived with a large number of texts, many of which were new to Japan and were esoteric in character, paintings of his predecessors, as well as several texts on the Sanskrit language and the Siddhaṃ script.
However, in Kūkai's absence Emperor Kanmu had died and was replaced by Emperor Heizei who exhibited no great enthusiasm for Buddhism. Kūkai's return from China was eclipsed by Saichō, the founder of the Tendai school, who found favor with the court during this time. Saichō had already had esoteric rites officially recognised by the court as an integral part of Tendai, and had already performed the abhisheka, or initiatory ritual, for the court by the time Kūkai returned to Japan. Later, with Emperor Kanmu's death, Saichō's fortunes began to wane.