Also written 研. Inkstone. A base made of stone or other material used for grinding *sumi 墨 ink sticks. One of the Four Treasures of the Study *bunbō shihō 文房四宝. Although most suzuri are made of stone, other popular materials included tile, clay, porcelain, jade, iron, copper, silver, wood, lacquer, and bamboo. The most common shapes are rectangular, square, round, oval, and free-form, and these may be either natural or manmade. The ink stick is rubbed with water on a flat, gently downward sloping surface that culminates in a small well for the ink.
The most important aspect of an inkstone is the quality of the stone, which is judged by how well it produces ink when rubbed. The Chinese inkstones produced from Duanqi (Jp: Tankei 端渓) in Guangdong 広東 province and Shezhou (Jp: Kyūjū 歙州) in Jiangxi 江西 province have been regarded as the best quality. Second in importance is the tradition associated with the ownership of a particular stone. If the inkstone was used by famous calligraphers or poets of the past, it is believed to link its current owner to some intangible essence of this previous personage. This is a quality prized by many literati in China and Japan.
Inkstones were first used in China, then transmitted to Korea and Japan. Suzuri from the 8th century have been excavated throughout Japan. Most are circular or free-form and made of either ceramic or tile. One famous inkstone preserved in the *Shōsōin 正倉院 in Nara is a free-form ceramic inset in the middle of a six-cornered blue-spotted stone. Although imported stone inkstones are known in Japan from the 9th century, most continued to be made from ceramic materials. But by the 10th century, stone inkstones were produced in Japan for daily use, and by the 12th-13th century, stone had supplanted ceramic. Although Chinese inkstones are still considered superior in quality, excellent inkstones are mined in many areas of Japan.