or 坏土. Raw materials that have been suitably processed to make them suitable for molding. The raw materials used for basecoat are mainly earth and stone, including pure porcelain clay and various types of clay, and feldspar, stone, pegmatite, quartzite, granite, and quartzite, as well as silica sand, bone ash, limestone, and white. The magnetic clay or clay clay is used to give plasticity to the clay and make it possible to form the clay, and it forms the core of the clay and is included in all ceramics. In the case of coarse stoneware, pottery, and earthenware, the clay is often a single component. Some are made from the decomposition of amakusa stone or quartzite, and contain clay, quartz, and feldspar, which can be used to make high-quality pottery clay.
However, most clay is prepared by mixing several kinds of raw materials to adjust its plasticity, fusibility, refractoriness, and color. For the production of crude products, the clay material is mined and kneaded without sifting, or it is simply sieved to remove coarse grains, and then water is added and kneaded to make cups. In all cases, the clay mined should be immediately processed and stored. Even though most of the clay is prepared in the form of plaster, some of the raw materials are prepared in a dry state and then watered, while others are prepared in a dry state and then mixed with water and finely ground. In rare cases, the entire dry process is used to prepare the clay. In ordinary cases, however, the prepared clay is in the form of plaster, and the excess water must be removed. When the water is removed and the clay has reached an appropriate consistency, it is kneaded. In the past, this was generally done with the hands and feet of a craftsman or with a pestle, but nowadays a kneading machine is used. (The Complete Works of Yaichiro Kitamura on Ceramics)
