Hyakuman-to Tower [also know as Hyakumanto Darani (The one million pagodas and Dharani prayers)] (百万塔)
The Hyakuman-to Towers were produced in the late Nara period at the wish of Emperor Shotoku. Hyakuman-to Towers were comprised of one million wooden sections of sanju no shoto (small towers with three stories, a three-tiered pagoda), and the wood for the project was formed through a process called rokuro-hiki (a lathe technique, composed of a potter's wheel and knife for shaping materials such as wood). One piece of Hyakuman-to Tower was formed in two parts, a pagoda and a Sorin (metal pinnacle on the top of pagodas), and the inside of the pagoda was structured to store a Darani.
The standard measurement used for the wooden sections in the Hyakuman-to Tower were, the tower height 21.4cm, the foundation base diameter 10.5cm, Pagoda height 13.4cm. The pagoda was made with the wood of the hinoki tree (a Japanese cypress), and the Sorin was made from the wood of sakaki tree (species of evergreen sacred to Shinto) and or the chinaberry (tree) a species of cherry. All parts in the tower were made from one piece of tree.
The pagoda was carved into a stylobate and three-tiered parts, then the top edge axis part was carved into the shape of a cylinder, then the cylinder had to be hollowed to store a Darani. As to the Sorin, all parts were carved in the following order, roban (dew basin at the bottom of a pagoda finial), fukubachi (inverted bowl-shaped part of a pagoda finial), horin (a part of the finial on top of a pagoda), and hoju (sacred gem). Then, the whole parts were coved with thick coats of white clay. The Sorin was fitted like a cover onto the top the pagoda. Some of the towers were constructed with production date and the full name of the manufacturer written in Indian ink on the back side of the foundation base, the upper part of the roof part, and the foundation base of Sorin.
In addition, besides the Hyakuman-to towers, there were productions of Nanae no shoto (small tower with seven stories), called 'Ichimansetsu-to Tower,' which contained 10,000 pieces in each constructed set. Then, the Jusanju no shoto (small tower with 13 stories), called 'Jumansetsu-to Tower' was a production with 100,000 pieces in each set.
In 764, after the Rebellion of Emi no Oshikatsu, the Emperor Shotoku ordered the production of the Hyakuman-to Towers, as he followed the views of "Muku joko dai darani kyo," specifically from the period of the Jingo Keiun era (767-770). A passage from 'May, 25, 770' written in the "Shoku Nihongi" (Chronicle of Japan Continued), stated with completion of the Hyakuman-to Tower, several temples would receive the set. The ten temples designated to receive the Hyakuman-to Towers set were kanji (state-sponsored temples): Daian-ji Temple, Gango-ji Temple, Kofuku-ji Temple, Yakushi-ji Temple, Todai-ji Temple, Saidai-ji Temple (Nara City), Horyu-ji Temple, Kawahara-dera Temple, Shitenno-ji Temple, and the Sufuku-ji Temple (Otsu City). Gango-ji Temple, Todai-ji Temple, and Saidai-ji Temple, were the only three of the ten temples that built a special structure called a "Shoto-in Temple." This would have been for the storage of the Hyakuman-to Tower, but only one Hyakuman-to Tower exist today; that tower was stored in the Taiho-zo-den in Horyu-ji Temple, 45,755 piece pagodas and 26,054 piece Sorins. In addition, there was an example of an abandoned and unfinished, possibly during production of a Hyakuman-to Tower, excavated from the site of the Heijo-kyu Palace.
The existence of the Hyakuman-to Tower speaks to the high level of interest in a Buddhism policy within the government, buttressed by the state's protection through out the Nara period. Also significant was the time and cost to develop the advanced woodworks technology and production system leading to today.