Akito Uchida
The temiya cave is a prehistoric site at Temiya, Otaru City,
Hokkaido, Japan. The cave measures approximately 5 x 3 m and is situated about 3 m above ground level under an overhang of a cliff. As a result of excavation by road construction and collapse of the cliff face, the cave today is little more than a recess (Fig. 1).
The Temiya cave is important from an anthropological and archaeological perspective because it contains ancient, engraved characters. In 1866, while prospecting in the cave for stone for building materials, a mason discovered the markings on an inner wall (Fig. 2). In 1920, the cave was designated a national historic site. Excavation research at the front of the cave in 1990 certified the characters as having been engraved about sixteen hundred years ago (Fig. 3).
Generally known as “ancient letters,” the characters are also described variously as inscriptions, symbols, and primitive art. However they are interpreted, these engravings are clearly recognized as valuable in terms of cultural heritage (Fig. 4).
Exfoliation and scaling of the cliff rock, a tuff, had become so extensive that it would have been increasingly difficult to identify the
Figure 1
The Temiya cave and its old shelter. Figure 2
Ancient, engraved characters.
Geological and Condition Survey
Figure 3
Excavation research.
Figure 4
Photogrammetric plot of the inscribed characters, 1993.
Characters if no conservation measures had been taken. The following describes the measures that have been and are currently being implemented for protection of the site.
A survey of the geology and condition of the rock was conducted at the Temiya cave in 1986 to obtain information about the geological features in and around the cave and cracks in the character-inscribed surface.1
Core samples 9 m long were taken by drilling into the cliff rock at two locations on either side of the existing protective shelter over the cave. Microscopic examination and dye-penetration observations were also carried out to determine the extent of weathering of the rock from the drill-core samples.
To investigate cracks and porosity in the wall surfaces inscribed with the ancient characters, infrared thermography, subsurface radar, and some measurements were made.
World History
