This is the process of making clay clay by using muddy water and using the buoyancy of the water to separate the fine and coarse particles. The process is generally limited to kaolin and plastic clay, and is used to produce porcelain, fine stoneware, ceramics, and terra cotta. The water process is omitted in order to obtain inexpensive products. The watering method should be appropriate according to the natural production conditions of the clay or the type of product, and is not necessarily constant, but the following three steps should be taken regardless of the method followed. (i) Throwing crushed clay into water and agitating it. (2) Separating the gravel or other coarse grains contained in the clay. (iii) Placing the separated fine-grained mud plasma in still water to gradually precipitate its clay content. It is not yet certain when the water weir process began in Japan. According to the “Bessho Kibei: The Book of Bessho Kibei’s Succession,” it is written that the first Fujishiro of Seto used silk to strain Ibe clay, and according to popular belief, the clay used for tea containers was first used by Kobori Enshu, who gave instructions. However, neither of these theories is worthy of belief.
It is thought that the water-blotting technique was introduced to Japan with the naturalization of the Korean potters. The method of separating the potter’s clay for the body and the glaze stone for the overglaze was introduced by water-sieving, which made it possible to use white overglaze that had never been used before. First, it was introduced to Karatsu, and then to Mino (Shino), and white transparent glaze came to be used in Japan, where only ash or iron glaze had been used so far.
The arrival of Korean potters brought with them ceramics manufacturing techniques from the continent. The clay and overglaze were produced from the same potter’s clay. Although feldspar, the raw material for glaze, is produced today, there was no concept of feldspar at that time (around 1600), and it is thought that clay and glaze were produced from the same clay by water-sieving.
The upper layer is used for clay because of its high kaolin content, the middle layer is used for glaze because of its high silica content, and the lower layer is ground again and re-sieved because of its large particles.
The technique that came from the continent includes the Chinese millstone, which plays another important role in addition to the water-sieving process.
The technique of using a Chinese mortar to grind the clay into fine particles and then separating the clay and glaze by water-sieving is a major point of innovation.
