Ishi no Hoden (Stone Treasure Hall)
This megalithic monument is enshrined as the main object of worship (shintai) at Oushiko Jinja Shrine. The enormous stone is hyaloclastite, an aggregate of fine, glassy debris formed by the sudden contact of magma and cold water, and stands 5.7 meters high, 6.4 meters wide, and 7.2 meters thick. It is estimated to weigh some 453,000 kilograms. The megalith rises out of a cavity in the bedrock on three sides and one of the sides has a triangular prism protrusion. The space between the monument and the bedrock is wide enough for one person to pass, and visitors can go around the whole megalith for a small fee.
Ishi no Hoden stands above a pool of water, and is situated on a pillar that is not readily visible, so the rock appears to be floating over the water. Traditionally, it was thought to be divine due to its distinctive appearance and unusual position and is also called Uki-ishi (Celestial Floating Stone) by local people.
Tatsuyama Tomb No. 1 is nearby. This is believed to be the burial place of a person connected with Ishi no Hoden.
Origin Story
The huge stone is recorded as having stood here about 1,300 years ago, but neither the reason why nor the stone’s significance are known. Many mysteries surround it. According to legend, in ancient times two gods named Onamuchi and Sukunahikona were sent as peacemakers from Izumo (present-day Shimane Prefecture) to this area, then called Harima (present-day Hyogo Prefecture), a province where there was unrest. They were granted one day to build a stone palace that would foster harmony, but their efforts were hindered by a rebellion of the gods of Harima who overran the area.
By the time the rebellion was suppressed, dawn had broken and the structure remained unfinished. Still, the two gods proclaimed that their spirits would reside within one of the massive remaining rocks and pacify the land for eternity. Today, this rock is known as Ishi no Hoden.
National Significance
Ishi no Hoden is mentioned in the Harima kokudo fudoki, an almanac presented to the emperor covering the years 713–717 for the region that is present-day Hyogo Prefecture. The document says the megalith was created by Mononobe no Moriya, a high-ranking clan head of the sixth century, on the orders of Prince Shotoku, but no reason is given.
Records from the Edo period (1603–1867) show that Oushiko Jinja Shrine was visited by many influential people, including German physician and botanist Philipp Franz von Siebold (1796–1866), who included three detailed sketches of the rock in one of his books on Japan. Since the twentieth century, the megalith has been considered a site flowing with spiritual energy, and is one of the three wonders of Japan.
In 2017, Ishi no Hoden and the nearby Tatsuyama Stone Quarries, which date from the Kofun period (ca. 250–552), were together designated a National Historic Site. The designated area covers approximately 11 hectares and comprises 49 cultural assets, making it a valuable heritage site.
