Long before the museum existed, the Togariishi ruins were already famous. The site sits on a plateau at the foot of Mount Yatsugatake at an elevation of 1,000 meters, where abundant spring water once supported dozens of Jomon communities. Although the ruins had been known since the Meiji period, it was the archaeologist Hidekazu Miyasaka who first excavated them in 1929. What he uncovered was extraordinary: 33 pit dwellings arranged in a U-shape around a central plaza, accompanied by Jomon pottery, stone tools, jewelry, and obsidian implements. The site measured roughly 170 meters east to west and 90 meters north to south. Beyond the dwellings, Miyasaka found 53 hearth sites, rows of standing stones, clay figurines, storage pits, and grave sites. This was the first confirmed example of a complete Jomon settlement in Japan -- not a handful of scattered artifacts, but the physical footprint of an entire community. The discovery made Togariishi the birthplace of Jomon settlement studies.

The Jomon Venus, excavated from the nearby Tanabatake site, is made from ocher-colored clay carefully polished and mixed with mica, giving it a subtle shimmer. Her exaggerated proportions -- the wide hips, the pronounced belly, the diminutive head -- place her firmly in the tradition of fertility figurines found across prehistoric cultures worldwide, yet her specific form is distinctly Jomon. The Masked Goddess, excavated from the Nakappara site in Chino and designated a National Treasure in 2014, poses a different kind of puzzle. She is larger, hollow, and her face is covered by what appears to be a triangular mask, with incised lines on top that resemble the cord used to tie such a mask in place -- or perhaps her eyebrows. A small hole near the point suggests a mouth; smaller holes above may indicate nostrils. Why a mask? Was she a representation of a ritual practitioner? A spirit? A priestess? The figurine offers no answers, only the unsettling beauty of a face deliberately hidden.

Togariishi is not an isolated site. Over fifty mid-Jomon settlement sites have been identified in the near vicinity, all clustered around the springs that flow down Yatsugatake's volcanic slopes. This concentration speaks to a landscape that was exceptionally productive for hunter-gatherer communities. The forests provided nuts, acorns, and game; the mountain's volcanic geology yielded obsidian for toolmaking; and the reliable spring water sustained year-round habitation at elevations that would have been punishingly cold in winter. Postwar excavations expanded the known scale of Togariishi itself, revealing at least 220 residence sites -- making it the largest settlement found in the Yatsugatake vicinity. The site was designated a National Historic Site in 1942 and upgraded to a Special National Historic Site in 1952, with the protected area expanded again in 1993. Despite the 'Stone Age' in its traditional Japanese name, the site has no connection to the Japanese Paleolithic period. The name is a historical artifact, predating modern archaeological terminology.

The museum, which opened in 2000, sits adjacent to the ruins themselves. Visitors can walk from climate-controlled galleries displaying the Jomon Venus and Masked Goddess out into the open-air site park, where reconstructed pit dwellings dot the plateau. The transition is immediate and visceral -- from glass cases and careful lighting to wind, grass, and the looming profile of Yatsugatake. The reconstructed dwellings are partially sunken into the earth, their roofs thatched, their interiors dim and cool. Standing inside one, you can see how the design works: the earth walls provide insulation, the central hearth provides heat and light, and the low entrance forces you to bow as you enter, a posture that feels unconsciously ceremonial. Outside, the same spring water that drew the Jomon people here still flows through the site, clear and cold, carving the same channels it has followed for thousands of years.