Mikawa Mu Valley

The Underground Kingdom of Mikawa is a theme park located in Iwakuni City, Yamaguchi Prefecture, which was renovated from the former site of a tungsten mine that was closed in 1982. In the cave, you can enjoy a riddle solving game where you can feel like Indiana Jones and read ancient letters. There is also an outdoor gold mining facility and a hot spring, making it a fun spot for families and friends alike.

[Entry fee]
Junior high school students and older: 1,800 yen
4 years old to elementary school students: 950 yen
[Gold dust collecting experience] 700 yen (time limit: 30 minutes)
[Natural stone digging experience: 700 yen (time limit: 20 minutes)
*Please present an official ID (passport, etc.) that verifies your age at the reception desk when entering the park to receive your discount.

The attraction of the Underground Kingdom of Mikawa Mo Valley is the long and wide cave that was created by reusing a tunnel. The cave is shaped like a large U, and is dotted with spots that remind you of ancient ruins, such as the “Mural Corridor,” where you can feel the remnants of ancient civilization, and the “Underground Waterfall,” where 2 tons of underground water flows out every minute. At the attraction, you can experience a riddle-solving game where you can solve the mystery of ancient letters and mysteries hidden in the cave. At the restaurant inside the facility, you can enjoy dishes such as pyramid curry with rice shaped like a pyramid.


740-05051564-1 Mikawamachi Nekasa, Iwakuni, Yamaguchi
10:00am - 5:00pm ※ Varies depending on the season.
Every Wednesday(Open during Spring Break, Golden Week, and Summer Break)
Janurary 1
※ Every Tuesday and Wednesday from December to February.