Hyakumanto Darani (The one million pagodas and Dharani prayers) (百万塔陀羅尼)
Hyakumanto Darani is the collection of Dharanis that was dedicated to Buddhist temples by way of being placed in one million mini pagodas during the Nara period for the protection of the nation as well as for repentance. The pagoda is called Hyakumanto (one million pagodas).
Background
Empress Shotoku, who had brought an end to the Rebellion of FUJIWARA no Nakamaro in 764, printed one million scrolls of Dharanis based on the "Pure Light Great Dharani Sutras" in 770, which took six years, for the purpose of mourning for the souls of departed warriors who were killed in action as well to pray for the protection of the nation. The scrolls were placed in mini pagodas, and pagodas containing 100,000 scrolls each were dedicated to Daian-ji Temple; Gango-ji Temple; Horyu-ji Temple; Todai-ji Temple; Saidai-ji Temple; Kofuku-ji Temple; Yakushi-ji Temple; Shitenno-ji Temple; Kawahara-dera Temple; and Sufuku-ji Temple (Otsu City).
Most of these pagodas have either been burnt in fires or have been scattered and lost; as of 2005, except for the 40,000-odd scrolls remaining in Horyu-ji Temple, only several of them are either kept in museums or are privately owned.
Summary
By convexly carving the Dharanis on a plate (whether the plate was of wood or metal is unclear), they were printed by casting a paper dyed from a Phellodendron amurense tree on top with a width of 4.5 cm and a length extending from 15 - 50 cm to prevent vermiculation. There is a theory purporting that it was printed by the sealing method by putting the paper underneath. As of 2005, it is said to be the oldest verifiable printed material in the world.
The mini pagodas where the Dharanis are placed are made up of small triple pagodas that are of a wooden make by using the traditional Chinese potter's wheel painted white.