Tosa TENGU (a kind of washi commonly known as Tosa Tengujo-shi in Japanese) is also referred to as “wings of a mayfly." Made from high-quality kozo, it is one distinctive kind of handmade washi that is both transparent and flexible.
The place of origin of this paper was not Tosa (an old name for Kochi Prefecture) but Gifu Prefecture, said to be the birthplace of paper in Japan. In the Muromachi period this paper was already being made, and in the Edo period it had various uses such as sketches for woodblock prints, tracing paper, and also in mounting and backing.
Sensing the future of these thin papers, Yoshii Genta placed an order for tengu from Gifu Prefecture, and began research and development on tengu that would be “larger and better quality." In 1880, the experimental forming of large-size tengu was a success. Also, in the following year tengu with a thickness of .03 millimeters was entered into the national exposition. Recognized as thin, working well with ink, and durable enough for typewriting, it received high praise as typewriter paper.
In this way, Tosa TENGU was first used as typewriter paper, but was also used for napkins, wrapping paper for precious stones, coffee filters, and lens cleaning paper. Most of the production was exported, and became known as ultimately thin paper under the name of "Tosa Stencil Paper."
However, after World War Ⅱ, due to the decrease of typewriter usage and the birth of machine-made tengu, there was a sudden decrease in the number of craftsmen. After this, machine-made paper inherited the demand once held by handmade paper, but over time production steadily declined. Traditionally-made paper was propped up by a limited demand, and continues a very small existence to this day.
Recently, however, much attention has been paid to the fact that Japanese historical documents and paintings have much higher levels of preservation than in other countries. Tosa TENGU became internationally recognized as good paper for restoration of cultural properties. As a result, world-renown cultural properties such as Michelangelo's wall paintings in the Vatican and works preserved in the Louvre in Paris began to use this paper for restoration purposes. Today the production of this paper is stable, largely thanks to machine-made paper technology. “The world’s thinnest, strongest paper,” developed by the dexterous techniques and aesthetic sensibilities of Japanese people, has received much acclaim over the last hundred years, and is now making a comeback.