Hayakawa Ishichobagun (Hayakawa stone quarry group)
Ishichoba is a quarry to cut stones used for stone walls in castles. Many stone quarries were built at the beginning of early modern history for the construction of Edo Castle in Hayakawa, Odawara City, where high-quality andesite from the Hakone volcano was produced. These are collectively called the Hayakawa Ishichobagun.
Andesite produced from the Hayakawa Ishichobagun is the lava that gushed out from the Hakone volcano about 300,000 to 230,000 years ago, and because it is characteristically hard and has few joints, is suitable for stone walls. Because of this, large stones as long as 2.7 m were cut out and used to the make the important corner “Sumi ish (corner stones)” that stone walls are stacked on.
So far, the Hayakawa Ishichobagun (Hayakawa stone quarry group) has only been confirmed to run east to west for 1.3km and south to north for 170m, covering a range of about 20ha on the current ground surface and most of it lies in the ground of the mountain forest. However, the remains of the stone quarry discovered and preserved during construction and the stone wall stones that were relocated and protected can be viewed.
In 2016 a part of the Hayakawa Ishichobagun was designated as a “Historic Site Edo Castle Ishigaki Ishichoba Ruins” and along with the Ishichoba (stone quarry) located in Atami City and Ito City, designated as a nationally historic site and will be preserved and passed on to future generations for many years to come.