Qualla: Akyū Ruins

Akyū Ruins: Introduction

Mon, 16 Feb 2026 00:00:00 GMT

Two hundred thousand river rocks, each the size of a fist, arranged in a donut-shaped ring 120 meters across. A central pillar assembled from 24 pieces of andesite. Seven hundred tombs encircling the whole complex. And all of it buried under a highway. The Akyu ruins in the village of Hara, at the southeastern foot of Mount Yatsugatake in Nagano Prefecture, contain the largest stone circle ever discovered in Japan, the centerpiece of a settlement that was continuously occupied for several thousand years during the Jomon period. When construction crews building the Chuo Expressway discovered the site in the 1970s, they faced an extraordinary dilemma: the planned route would destroy it completely. Their solution was equally extraordinary. After a thorough excavation in 1975, the site was carefully backfilled, and the expressway was built directly on top of the fill layer, entombing the ruins in a kind of protective cocoon beneath the asphalt.

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Akyū Ruins: Layers Beneath the Pavement

Mon, 16 Feb 2026 00:00:00 GMT

The Akyu site sits at 904 meters elevation on a ridge between the Aku and Ohaya Rivers, covering 56,000 square meters. Excavations revealed a settlement that evolved through three distinct cultural phases, providing an unusually clear window into how Jomon communities transformed...

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Akyū Ruins: A Ring of River Stones

Mon, 16 Feb 2026 00:00:00 GMT

The stone circle at Akyu is staggering in scale. Its donut shape measures 120 meters at its widest and 90 meters at its narrowest, filled with an estimated 200,000 fist-sized river rocks hauled from nearby waterways. At the center stands a pillar 1.34 meters tall, assembled from ...

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Akyū Ruins: The Yatsugatake Corridor

Mon, 16 Feb 2026 00:00:00 GMT

The Akyu ruins do not exist in isolation. The area surrounding Mount Yatsugatake has one of the densest concentrations of Jomon settlement sites anywhere in Japan. Immediately to the north lies the Togariishi ruins, and to the south the Idojiri ruins, both major settlements from ...

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Akyū Ruins: Preserved in Darkness

Mon, 16 Feb 2026 00:00:00 GMT

The decision to bury the Akyu ruins rather than relocate or destroy them was a remarkable act of preservation through concealment. The expressway now passes overhead, its drivers unaware of the ancient settlement beneath their wheels. Some of the artifacts recovered during the 19...

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