Here, we have one of very few Jomon period (14,000 – 1000 BCE) obsidian mines left in the country. “Hoshikuso” is what the Jomon people of this area used to call obsidian, believing it to be the excrement (kuso) of falling stars (hoshi). This exhibition showcases a preserved section of an underground obsidian mine.

The Jomon people exported their obsidian, a rare resource in those days, all around Japan. The first signs of this mine site were discovered in 1991, and excavation work has been continuing ever since. The formation of strata (layers of rock) tells us a lot about what the mine would have looked like back in the Jomon period.

You can still see the wooden poles put in to prevent cave-ins, 5 metres below ground level. You can also spot the wooden tools and lacquered prayer boards which were discovered around the mine. These prayer boards were left by the Jomon people, praying for their safety as they worked in the mines.