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Mystery surrounds 'pyramid' mountain thought to have been sacred ancient Japan site

Mount Kuromata, which is known for its pyramid-like shape, is seen in the city of Kazuno, Akita Prefecture, on July 12, 2021. (Hikoshi Tamura)

KAZUNO, Akita -- A pyramid-shaped mountain in this northeastern Japan city known as "the mountain of many mysteries" among myth enthusiasts is thought to have been a special sacred spot for people in ancient times.

    Mount Kuromata, commonly known by the name "Kuromanta," stands 280 meters above sea level in the Akita Prefecture city of Kazuno. Two kilometers southwest are the Oyu Stone Circles, which are part of a series of archeological sites from the Japanese prehistoric Jomon period in Hokkaido and the northern Tohoku region. They are set to be placed on the World Heritage List. The stone circles are believed to have had some sort of connection with this mountain in the past.

    A torii gate of Motomiya Shrine stands at the trailhead of Mount Kuromata in the city of Kazuno, Akita Prefecture, on July 8, 2021. (Hikoshi Tamura)

    When viewed from a distance, the mountain has orderly triangular-shaped sides, earning it the nickname "Japan's pyramid." The local name "Kuromanta" is said to have roots in the Ainu language, and legend also has it that the site is a tumulus where Kurosawa Manta, the head of the local community in ancient times, was interred. At the mountaintop is Motomiya Shrine, whose torii gate is located at the mountain's trailhead.

    The theory that Mount Kuromata is an ancient pyramid has endured among experts. In the 1990s, a group consisting of archaeologists gathered specialists on Shinto folklore studies, cultural anthropologists and others for an investigation to try to get to the bottom of the mountain's mysteries.

    According to the investigative report published March 1995, an underground radar-based probe detected a reaction indicating the existence of artificial structures in the underground area below the summit -- which is also the area beneath the Shinto shrine's main building.

    The possibility emerged that the mountaintop could be a man-made hill. The report concluded that there were "strong suggestions that the site was built with specific objectives, by restructuring the mountain in nature, as well as building artificial structures." In other words, Mount Kuromata is believed to be a step pyramid-shaped ritual site.

    Yasuo Abe is seen in an area at the summit of Mount Kuromata where a deity is said to have landed, in the city of Kazuno, Akita Prefecture, on July 8, 2021. (Hikoshi Tamura)

    A doctor who was the kin of a warrior in the mid-Heian period (794-1185) that ruled the Emishi population in northeastern Japan escaped near Mount Kuromata, and enshrined a healing deity in the mountain. Earthenware fragments from the late Jomon period and Yayoi period, as well as parts of the stone circles, were excavated here, suggesting this whole mountain was considered a sacred place among ancient peoples.

    The mountain is also known as the subject of a painting by artist Toya Banzan (1876-1966), who depicted a mysterious object flying overhead while emitting light. Yasuo Abe, 70, who is the head of the area's tourist association and an expert on the mythology surrounding the mountain, said, "Though it's originally thought to be a natural volcanic mountain, it has been worshipped in the community as a special mountain."

    (Japanese original by Hikoshi Tamura)

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