A type of Chinese paper imported and used in Japan for painting and calligraphy and as backing paper urazuke 裏付 for mounting and binding. See *karakami 唐紙. Approximately 132 cm x 162 cm, tōshi is made from mulberry and bamboo fibers mixed with caustic soda, which creates a rough surface and a light brown color. The use of bamboo fibers weakens the paper because it resists bonding, but two types of bamboo, keichiku 桂竹 and mōsōchiku 孟宗竹 (Phyllostachys pubescens; a thick stemmed bamboo) were commonly used. Tōshi was valued for its low water absorbency which made it suitable for calligraphy without applying glaze *dōsa 礬水. A Japanese version of the paper, also known as tōshi, or watōshi 和唐紙, was used for calligraphy. Taiwan tōshi 台湾唐紙 and ryūkyū tōshi 琉球唐紙 (from Taiwan and Okinawa respectively) also exist, but Chinese tōshi is considered to be of the highest quality.
According to *Shōsōin 正倉院 records, tōshi was used as early as the Nara period for copying Buddhist sutras. Genji monogatari 源氏物語 (The Tale of Genji) and other Heian period documents claim that members of high society used tōshi that was dyed various colors such as yellow, purple, or pale blue. A large quantity and variety of tōshi was imported from China until the beginning of the 19th century, when the number of boats coming to Japan was temporarily reduced and production of Japanese tōshi rapidly increased, especially in the Edo region. Although tōshi was very widely used up to the end of Edo period, *gasenshi 画仙紙 is more commonly used today.
The most usual type of tōshi, called ichiban tōshi 一番唐紙, is considered to be of relatively low quality, but it highlights differences between pale and strong shades of ink. This makes it very suitable for calligraphy or paintings using pale shades. Niban tōshi 二番唐紙 is a higher quality paper with a smooth surface and low ink absorbency, and so very easy to use. It is an excellent paper for writing, drawing, painting, and calligraphy practice. Sanban tōshi 三番唐紙 is a Japanese made tōshi, and is a thick, rough surfaced paper similar to ichiban tōshi.