The Mysterious Ishi no Hoden Megalith

Ishi no Hoden

There is an object attached to a boulder about 100 kilometers (62 miles) from Asuka Historical Park, near the town of Takasago (Japan). The object is a megalith with a size of 5.7 by 6.4 by 7.2 meters (18.7×20.9×23.6 feet) and weighs about 500-600 tons.

Ishi no Hoden – that is the name of the megalith which is kind of “semi manufactured” because it was left in the place where it was built, and clearly it hadn’t been completely finished.

There is a piece in the form of a cut-down prism on one of its vertical sides, which suggests that the object is lying in its side. This type of position looks strange only at first look. The megalith is hard to photograph, and the Shinto temple rising above it looks like an air structure next to this giant boulder.

The temple is built precisely in that place because the megalith is believed to be holy and people have venerated it since ancient times. The official version is that the rock was meant to be a tomb. But there is no scientific information as to who built it and with what purpose.

There is a large stone reservoir in the shape of a tray underneath the monolith and it is filled with water. According to temple records, this water reservoir never dries up, not even during periods of lengthy droughts. Because of the water, the base of the megalith which connects it with the ground cannot be seen, and it looks as if the megalith is floating in the air. That is why Ishi no Hoden’s other name is “the departing stone”.


Takasago city council, along with the History laboratory in Otemae University organized studies of the megalith in 2005-2006 – three-dimensional measurements were taken, and the characteristics of neighboring rocks were also observed.

At first look, the surface of the megalith appears to be handmade, but there are no traces of pickaxes or other instruments. Such traces can only be found underneath the megalith, where it is attached to the larger boulder. The lack of such traces can be due to erosion, but Ishi no Hoden had been covered by rubble (from the top of the mountain) which most likely was a result of some earthquake. In time, the space around the megalith was cleared. According to available sources, Ishi no Hoden was not built from granite, but from hialoclastite (a pyroclastic, glassy rock), that was formed from volcanic eruptions in the water about 70 million years ago.

The lack of traces on the rock around the megalith is even more puzzling. There are no traces – neither from machines, nor from hand tools. The whole rock is literally “pristine clean” of whatever traces. The lack of traces from pickaxes and chisels on the rock around Ishi no Hoden can only mean one thing – such simple instruments were not used when cutting the rock, but what other tools could have been used?

There are no signs of machine work, which would mean that whatever technology was used is unknown to us. As was mentioned, the official version is that the megalith was meant to be a tomb, and that is obviously why researchers were look for cavities in it. According to locals, only sarcophagi were made from monoliths and it was only for their lid which was always separate from the rest of the sarcophagus. But Ishi no Hoden looks nothing like a sarcophagus – it is way too big.

Historians have no other theories as to the purpose of the megalith. Although there are clues, however indirect, that Ishi no Hoden was built by a technologically developed civilization. This seems possible, not only because there are no traces from manual work on the material, but also because it is so large. Whoever built it probably experienced no difficulty whatsoever to move 500 tons of rock.

Local citizens connect Ishi no Hoden with the work of some “gods”. According to legends, two gods participated in the making of the megalith – Ōkuninushi (great land master) and Sukuna-biko-na. When they arrived, they were supposed to build an entire castle in one night, but they got only to Ishi no Hoden when local Gods rebelled. The two Gods hurried to stop the rebellion, the night ended and the castle was left unfinished. But both Gods swore to protect this land.