Kagekiyo Cave

Kagekiyo Cave: A Limestone Cave With a Heike Legend

Kagekiyo Cave (景清穴, Kagekiyo-ana) is a limestone cave in Mito-cho Aka, Mine City, Yamaguchi Prefecture, designated a national Natural Monument in 1922. It is better known locally as Kagekiyo-do.

According to Mine City, Kagekiyo Cave lies at the southwestern foot of Inodedai, at the northeastern tip of the Akiyoshidai plateau. Its passage runs roughly north and connects underground with the Sanmida and Sue caves. It was once called Chosei-do, or Aka-no-ana after the village, and took the name Kagekiyo from one of its side passages.

The cave is about 1.5 kilometres long, and Mine City notes that the side passages might double that. The mouth sits at the foot of a cliff 30 metres high, a rough triangle 45 metres across and 16 metres high.

Why It Was Designated, and the Legend

Mine City stresses the link with Sanmida Cave. The Sanmida River, crossing the Sanmida polje, sinks underground and flows through Kagekiyo Cave to emerge in the Sayama polje: a textbook through-cave with a stream on its floor, which the city calls unlike any other. The ceiling and walls hold countless fossils of corals and crinoids.

The name recalls Oba Kagekiyo, a Heike warrior. Legend says the Oba clan fled here after defeat at Dan-no-ura and that Kagekiyo and other young swordsmen drove off the troops sent after them; the Edo-period survey Chushin-an records that Heike fugitives sheltered here. The same text notes that the young lord of the domain came to see the cave in 1830, and that a wandering ascetic praised it as without equal in Japan.

The designation note reproduced on Cultural Heritage Online is almost word for word the same as the one for Akiyoshido, which calls that cave the largest in Japan. For the size of Kagekiyo Cave this article follows Mine City's figures instead.

What to Look For

Named spots follow one after another: side caves such as Rakan-ana and Kaza-ana, and formations called Ikime Hachiman, Tengu-iwa, Kagekiyo Tsurara, Eboshi Tenjo, Sango Tenjo and the Dragon's Shed Skin. Look closely at the ceiling and walls for fusulinids, corals and seaweed fossils.

The first 700 metres or so from the entrance form a level show route passable by wheelchair. Beyond it runs an unlit exploration course of about 400 metres, walked with a borrowed helmet, headlamp and boots through the cave in its natural state. It takes about 60 minutes and needs no booking.

Mine City also records a local rule: enter at Kagekiyo and come out at Sanmida, never the other way, or misfortune will fall on the village.

Visiting Kagekiyo Cave

Kagekiyo Cave admits visitors from 9:00 a.m. to 4:30 p.m., every day. Following a revision in October 2025, admission is 1,300 yen for adults, 1,200 yen for junior high school students and 700 yen for elementary pupils; the exploration course, including admission, is 1,400 yen for adults and 900 yen for children. A combined ticket with Taisho Cave is also sold.

By car it is about 5 minutes from the Edo interchange on the Ogori-Hagi Road. Enquiries go to Kagekiyo-do on 08396-2-2201.