As an affiliate department of Zushoryo (the Bureau of Drawings and Books) under the Ritsuryo system (a system of centralized government based on the ritsuryo code), Kamiyain manufactured paper used in the Imperial Court.
It was sometimes abbreviated to 'Kamiya.'
It produced new paper for public or private use in the Imperial Court, and recycled paper called sukigaeshi-gami (paper made from dissolved old paper), or shuku-gami. Paper manufactured by Kamiyain was called kamiyashi, which was found in a record from 728 ('Shoso-in monjo' (Documents of Shoso-in)). According to the Yoro Ritsuryo Code (code promulgated in the Yoro era), there were four zoshishu, or paper making technicians, who belonged to Zushonoryo, and 50 kamiko (hereditary artisans for paper making under the government management) belonging to Shinabe (a rank of technicians in offices), who worked under zoshishu, were placed in Yamashiro Province.
With the establishment of Heian-kyo (the ancient capital of Japan in current Kyoto), Kamiyain was moved to a riverside of Tenjin-gawa River in Sagano, and its facilities were improved. The Engishiki (an ancient book for codes and procedures on national rites and prayers) stipulated that a total of twenty thousand sheets of paper such as fushi (cloth made of paper threads), kokushi (paper made from paper mulberry tree), mashi (paper made from hemp), hishi (high-quality paper made from gampi tree), and kujinshi (paper made from sophora plant) should be produced, and delivered to Kuraryo (Bureau of Palace Storehouses) every year.
Although Kamiyain was abolished during the period of Northern and Southern Courts, paper manufacturers in Kyoto took over Kamiyain's artisans and technology intact, and Shukushikamiza, which was kamiza (a trading association of paper manufacturers and distributors) with Kurododokoro (the Chamberlain's Office) as its honjo (proprietor or guarantor), is said to have been one of their descendants.