Ehime / Are marine megaliths man-made? （愛媛／「海上の巨石群 人工物？」）
Shimpei Okuhara Yomiuri Shimbun Staff Writer
Ancient monument or natural feature? Five massive granite boulders off Shiraishi-no-hana cape in Matsuyama are attracting attention since it was noticed that the formation seems to function as a solar calendar.
As rays from the setting sun pass through a gap in the boulders around the time of the spring and autumn equinox, local historians established an investigative committee in April to study whether the megaliths had a religious function. They set up a Web site and asked Ehime University and other entities to support their research.
The megaliths lie 50 meters off Shiraishi-no-hana--the name means "the nose of Shiraishi." The five boulders, stacked against and atop each other, measure about 20 meters in circumference and about six meters in height. The gap in the lower section is two meters high and 50 centimeters wide. Their gross weight is estimated to be more than 100 tons. The committee named them Hakuryunoishi (White dragon rocks).
Local historian Kunihiko Shinozawa, 45, started studying the rocks in January last year as he suspected they were placed there by humans. In addition the rays of the setting sun beaming through the gap in the boulders at the equinoxes, he found a rock that seemed to have been driven into the base of the giant rocks. There were also traces that humans had worked at the rocks because this could not be explained by wave or wind erosion.
When Shinozawa sounded out the prefectural board of education in August over whether it could preserve the megaliths as a cultural property, the board said an academic investigation by a public third-party organization was needed first.
Shinozawa then started trying to raise the profile of the issue by, for example, presenting the results of his studies at the Ishikawa Summit conference of megalith researchers in Kobe in September and contributing an article on the megaliths to the December issue of Rekishi Kenkyu, the journal of the national society for history research, to publicize the megaliths. He also set up the Matsuyama Shiraishinohana Megaliths Laboratory, which has its own Web site (http://haku1414.web.fc2.com/).
Shinozawa has held a viewing event for local residents on four occasions, including the spring equinox. Kunisato Takechi, 41, a priest at the local Katsuoka Hachiman Shrine, said he was moved by the beautiful sunrays that shone through the gap in the rocks and suggested the megaliths could become a tourist attraction.
Some megalith formations in Gifu and Kochi prefectures and several other ruins are thought to have been used to chart the passage of the seasons as sunlight shines through apertures in them at astronomically significant dates.
"I want to revitalize the local community by preserving the megaliths as a cultural property after studying them," Shinozawa said.