The basic research for assignment of the date on cultural properties of paper materials(documents, classical books, the sacred teachings, drawings)

The object of this research is to establish the method to assign the date on cultural properties of paper materials, which is not clearly written its manufactured date. The way was done by optical observation, that is, undestructive investigation. To do so, we investigated these cultural properties, especially, the writing paper of original documents, going to the institution which is possessed to them. Main ones of them, are the Documents of Daitokuji Temple, Toji-Hyakugomonjo, Todaiji-Monjo, ect... They amount to 15.000 in all. Also, about the writing paper of documents of pre-modern age, to ascertain if the papers will actually be made by the way we assigned, we experimented in making of Suibaragami, Otakadanshi, or something, in cooperation with Kochi technical center of the Paper Industry. Consequently, the first result we can confirm is the full provision of the objective data of writ ing papers from medieval ages to modern ones trough. The second result is that, as to the writing papers of ancient manuscript, we clarified the outline of their changing with the time and the method of optical judgement of them. We think we came to be able to make a conformable suggestion.