The cave brewery was originally developed as a site for an underground factory manufacturing parts for military tanks around the end of World War II. In November, 1944, when the decision was made to evacuate Tokyo Doryoku Seizo Company, a semi-underground factory was built at the foot of the mountain and this factory was built next to it. It is said that about 20 military tanks were manufactured in the semi-underground factory by the end of the war but since the war was nearing its end, this un