Excavated Kawarayato Kiln Site

Kawarayato Kiln Site and Excavated Artifacts (Tokyo Designated Historic Site / Tokyo Designated Tangible Cultural Property)

The Kawarayato Kiln Site is located along Kawasaki Kaido on the west side of City Hospital in Omaru, Inagi City. This site is known as a kiln site where roof tiles for Musashi Kokubunji were fired during the Nara period. The first excavation survey was conducted in 1956, organized by Inagi Village. During this survey, two kiln sites were discovered, revealing that these kilns produced roof tiles from the founding period of Musashi Kokubunji and square tiles related to the Musashi provincial government office.
In 1998, a second excavation survey was conducted in conjunction with the widening work of Kawasaki Kaido. This survey covered the western part of the area investigated in 1956. A preliminary survey was carried out in 1997, and the main survey began on March 3, 1998. For convenience, points A, B, and C were set from the east side, and excavations were carried out sequentially. As a result, one kiln site and one ash layer were confirmed at point A, one kiln site at point B, and one ash layer at point C (an ash layer is a place where ash accumulated in the kiln was scraped out, with ash and discarded roof tiles piled up in front of the kiln’s firebox). Excavated artifacts include round roof tiles (male tiles), flat roof tiles (female tiles), eave round tiles (abumi tiles), eave flat tiles (u tiles), decorative tiles, square tiles, rectangular tiles, Sue ware, and others. The excavation survey yielded many results and was completed on August 17, 1998.

Two Excavated Tile Kiln Sites

Kiln A, discovered at the eastern end of point A, was mostly destroyed by a concrete retaining wall, with only a small part of the firebox and the front courtyard remaining. The overall form is unknown, but it is highly likely to have been an underground climbing kiln. An ash layer spread out on the southwest side of the kiln site.
Kiln B is an underground, multi-level, stepped climbing kiln carved out of the Inagi sand layer at point B. It was discovered in an almost complete form, with the kiln body measuring approximately 6.5 meters in total length and about 1.8 meters at its widest point, and a height of about 5.5 meters from the firebox to the top of the flue. Inside the kiln’s firing chamber, seven tiers were constructed for firing roof tiles, and some of these tiers were reinforced with "sen" to make it easier to place the products.

Line engraving of a horse drawn inside the kiln site

A line engraving of horses was discovered on the right side wall of the combustion chamber inside Kiln B, attracting attention. Within an area of approximately 1 meter by 0.6 meters on the side wall, three horses were depicted, engraved with a stick-like tool. The two horses drawn at the lower part were expressed with dynamic lines showing saddles, hooves, and manes, while the one horse drawn at the upper part was depicted with simple lines, opposite to the lower two. It is believed that the horse line engravings were used in rituals related to the kiln hearth. Praying to the fire god when building and firing a kiln is a custom still practiced today. The discovery of horse line engravings inside a kiln is the first of its kind in Japan.

Square Brick Inscribed with a Written Statement

The written statement is a petition from the village head to the county office, inscribed on a square brick (a brick-like ceramic tile used for building floors, approximately 28 centimeters in both length and width, and about 8 centimeters thick). The inscription consists of 13 characters: "蒲田郷長謹解申　武蔵国荏原郡," which is read as "Kamatagō no osa tsutsushimite geshi mōsu, Musashi no kuni Ebara-gun." This is a petition from the village head of Kamata Village (around present-day Ota Ward) addressed to the Ebara County office, which governed parts of Shinagawa and Ota Wards. It is a valuable document indicating that, at the time of the construction of the Kokubunji temples, a basic labor tax system of one country, one county, one village, and one household had been established. Additionally, a "practice brick" believed to have been used for practicing writing before inscribing the official statement was also discovered simultaneously.

Relationship with Musashi Kokubunji and Musashi Kokufu

The Kawadaniyato kiln site and Musashi Kokubunji and Musashi Kokufu are located at a close distance of approximately 3.5 to 4 kilometers in a straight line across the Tamagawa River. This investigation revealed that the tiles and bricks fired at the Kawadaniyato kiln site were used during the founding period of Musashi Kokubunji and for Musashi Kokufu. In particular, the square bricks were identified as being for Musashi Kokufu, while the rectangular bricks were for Musashi Kokubunji.

References.
"Kawataniyato Kiln Site Excavation Report"
"Inagi City Cultural Property Research Bulletin Nos. 2, 3, and 4"