Goa Jepang No. 1 marks the boundary of the Kawasan Goa Jepang complex, crossing the border line into Purwosari, Gunungkidul.
Identified as a specialized defense outpost for troop shelter and ammunition storage, the heavily reinforced concrete structure was long forgotten and buried under hillside sediment until government excavations cleared it for visitors.
If you look closely at the entrance concrete, you can still see the original groove lines where the military wooden door frames used to slide into place.
Also read the main article about Kawasan Goa Jepang.
