National Treasures & Important Cultural Properties
of National Institutes for Cultural Heritage, Japan

This is an esoteric Buddhist commentary by Kûkai (774-835, posthumously known as Kôbô Daishi) that explains the title of the Vajracchedika Sutra (J. Nôdan kongô hannyaharamitsu kyô, popularly known as the Diamond Sutra). A kaidai is a formal interpretation of the title of a sutra and explication of its importance. However, since additions and corrections can be found throughout this manuscript, it is regarded a draft.

The Diamond Sutra itself has six Chinese translations of which the one by Kumarajiva is most frequently used. However, the version that Kûkai used for his interpretation was that translated by the monk Yijing (J. Gijô, 635-713) of the Tang dynasty (618-907). The Diamond Sutra attracted many devotees in Tang China, and stories of its miraculous power to benefit believers were compiled in the Collection on the Efficacy of Adamantine Wisdom (Ch. Jingang banruo jiyanji; J. Kongô hannya shûgenki). The sutra also had a strong following in Japan. By the Nara period (710-794), a large number of copies was produced by the Imperial Office for Sutra Copying. During the Heian period (794-1185), belief in the powers and efficacy of this sutra grew even stronger. Stories from the Collection on the Efficacy of Adamantine Wisdom, brought from China, were collected in Japanese compilations of Buddhist tales such as Miraculous Stories of Karmic Retribution of Good and Evil in Japan (J. Nihon ryôiki), the Collection of Tales of Times Now Past (J. Konjaku monogatarishû).

Sanpô-in Temple of the Daigô-ji Monastery in Kyoto is believed to have originally owned the Kongô hannyakyô kaidai commentary. At some point, however, it was removed from the temple and cut into sections. The extant sections of the manuscript total about 150 lines. This segment in thirty-eight line was owned by the Takamatsu-no-miya family. A sixty-three-line segment in the collection of the Kyoto National Museum and other fragments (J. dankan) are also known to exist. An eighty-six-line segment that was part of the first section of the original manuscript was destroyed by fire during the Great Tokyo Earthquake of 1923 (Taishô 12).

In the tenth month of 813 (Kônin 4), Fujiwara Kadonomaro (715-818) completed 187 copies of the Diamond Sutra as an offering (J. kuyô). Some years earlier, in 804 (Enryaku 23), Kadonomaro had traveled to the continent as an ambassador to Tang China on the same boat as Kûkai. Their ship had met with a violent storm, and they drifted at sea for more than a month. At that time, Kadonomaro made a vow to 187 deities that he would make an offering of a copy of the Diamond Sutra to each one if the ship were spared. They eventually reached port safely, and Kadonomaro honored his promise by offering187 copies of the Diamond Sutra to the gods. Kûkai wrote the dedicatory prayer (J. ganmon) for Kadonomaro, and it is thought that Kongô hannyakyô kaidai was authored at the same time.