kawara 瓦

Keywords
Architecture
Roofing Tiles

Lit. tile. The roofing material made of fired clay introduced to Japan from Korea (Paekche Kingdom, Jp: *Kudara 百済) during the 6th century along with Buddhism. During the 570s at the time of the reign of Emperor Bidatsu 敏達 (reign, 572-85), the king of Paekche sent six people to Japan skilled in various aspects of Buddhism, including a temple architect. According to the Nihon shoki 日本書紀 (Chronicles of Japan) a temple was founded by Prince Ohowake of Naniwa. In 588 more tile makers and architects were among the specialists sent to Japan. In that year the temple of Hōkōji 法興寺 (Asukadera 飛鳥寺), Nara, was begun. Many of the oldest roof tiles in Japan have been excavated from this site. Tiled roofs were used for temple and government buildings but for the emperors' palaces and dwellings of the nobility, traditional materials such as miscanthus reeds *kayabuki 茅葺 were preferred. In regard to the content of the clay, an interesting statement is found in the Engishiki 延喜式 Takumiryō 木工寮 Sakuga (Tile Making and Wood working Styles in the Engi period; a 10th-century Japanese document) which states that after the middle of the 8th century, it was common practice to mix 24 kilograms of clay with 10 liters of sand. This mixture, it goes on to say, is easier to shape and allows less shrinkage when fired than the higher quality clay used previously. There are two known techniques for manufacturing clay roof tiles. One is the Cylindrical Mold Method, which until recently was used in Okinawa and Korea. The other one is the Curved Mold Method which has been used in Japan (except Okinawa) since the middle of the 7th century. With the former method, well kneaded clay is firmly packed into a trapezoidal pile. Sticks are set on each side at a fixed distance from the top, and with a tool like a large cheese cutter, a slice is removed from the surface. This is repeated again and again depending upon the desired number of tiles. A wooden cylinder is placed on a turning plate, a tool like a slow potter's wheel, and the cylinder is then covered with cloth made of banana fiber (in Okinawa) or hemp or ramie (in Korea). At the top and bottom of the cloth is a string used for removing the finished tile from the form and then for removing the cloth from the clay. As can be seen the slice of clay has been pressed around the cylinder and smoothed and shaped as the plate revolved. When the tile is finished and removed from the cylinder, it is allowed to dry for a day or two. Especially notice are two sticks protruding from the top of the wooden cylinder. These may number two or four depending upon how many pieces the tile will be divided into. Where the stick is inserted, the clay is thin, and after it has dried out it can be tapped lightly to sever it into the required number of pieces. If the cylinder is divided into two, it will form round roof tiles; if it is separated into four parts, these will become flat roof tiles. It shows clay on cylinders. Notice that one clay circular form is inverted and another placed on top to dry. The second method, the Curved Mold Technique, used in Japan proper, depends upon individual molds already in the shape of the desired tile. It shows a mold for a circular tile. Most roof tiles were fired once and used immediately afterward. However, some glazed tiles have been found at palace sites, for example, at the 8th-century Japanese capital of Heijōkyō 平城京 in Nara and the 9th to 12th-century site of Heiankyō 平安京 in Kyoto. Not enough glazed tile has been recovered to be convinced that entire roofs were made of this. Mainly ornamental plates have been recovered, which would seem to indicate that perhaps the glazed tiles were placed only at the edges. Some of the earliest tiles studied seem to show traces of red ochre, black and some white, which appears to be some sort of lime or chalk, rather than paint.