Obsidian Production Area of Himeshima

One Source of Obsidian, Designated by the State in 2007

Obsidian Production Area of Himeshima (姫島の黒曜石産地) lies in Himeshima village, Higashikunisaki District, Oita Prefecture, and was designated by the state on 26 July 2007. Its category is that of natural monuments.

The field for a managing body stands empty.

The Agency records the island as a known source of the obsidian tools that spread widely across south-western Japan from the Jomon into the Yayoi period.

Two Methods, Two Very Different Dates

For the same rock, the figures do not agree.

The Agency records the absolute age of the obsidian as measured on the rock exposed at one headland: 320,000 to 340,000 years by fission track, and 200,000 years by the potassium-argon method.

Both methods date rock. From one material they differ by 120,000 to 140,000 years.

At the Bingo provincial seat, a written record was borne out by excavation: a supposition confirmed.

At Hibakoiwa Cave, the marks on the pottery tell the period.

Here two figures stand side by side. Neither is chosen over the other; both are set down.

An Island Made of Seven Volcanoes

One island is described as a gathering of volcanoes.

The Agency records that it belongs to a volcanic group of 7 volcanoes, formed by a run of activity beginning about 300,000 years ago.

Seven are distinguished by name.

Each is built of a lava dome, or of the tuff rings and tuff cones thrown up where magma met water. This, the record says, tells of violent eruption near the surface of the sea.

At Futatsuzuka Kofun, one mound holds 3 stone chambers: work of human hands.

Here it is the land itself that is counted, and counted in sevens.

A Designation Confined to One Part of the Island

Not the whole island, but a quarter of it, is designated.

The Agency records that what falls within the designated area is one crater and the lava dome that rings it.

Of the 7, the volcano in the north-west is built of a glassy rhyolite lava dome bearing garnet, with 2 craters.

One of those craters, with the ground about it, is the designated area.

At the okichimozuku habitat, 3 separate stretches of river are designated: distinct places set side by side.

Here one quarter is cut from a single whole. The name carries the island, and the designation does not carry all of it.

Visiting

The site lies in Himeshima village, Higashikunisaki District, Oita Prefecture.

The Agency records the island 4 kilometres off a peninsula in the Inland Sea: 17 kilometres around, 7 kilometres east to west and 3 kilometres north to south, long and narrow, rising to 266.6 metres at its highest point near the centre.

Most of the lava there is milky white and very finely vesicular; around the one crater it turns ashen black, and that is the obsidian.

As material for stone tools, the record adds, it is known to have travelled to another prefecture and to the south-west of a neighbouring island from the Palaeolithic into the Yayoi period. Stone from the island crossed the sea.

This is a coast on an outlying island, and whether and how it may be visited follows the arrangements of the local authority. Check before travelling.