How Did the Jomon Rise and Fall? Survivors, Stone Circles and an Origin No One Has Found

I have spent years investigating the Jomon period and traveling repeatedly through Tohoku, and everywhere I go I sense the traces of a past flourishing that stands in sharp contrast to the region’s depopulated present.

While the east—long the vibrant center of Jomon civilization—experienced a severe contraction, western Japan, previously quiet by comparison, held comparatively steady. This divergence between eastern decline and western stability set the stage for what followed: an explosive population surge in western Japan during the subsequent Yayoi period, and the eventual relocation of Japan’s political center to the west during the Kofun period.

But the returning cold confronted them with the stark struggle for survival, causing numbers to crash. Crucially, this global cooling triggered upheavals across the sea on the Asian mainland as well—a development that would bring the ten-thousand-year Jomon epoch to its close.

While determining exact figures remains elusive, it is widely accepted that numbers surged between the Early and Middle Jomon periods (roughly 7,000 to 4,500 years ago), reaching a peak during Middle Jomon estimated at over 250,000 people across the islands. Deduced from the distribution of settlements and pit dwellings, this density was concentrated overwhelmingly in eastern Japan.

At the Sannai-Maruyama site in Aomori Prefecture, the largest known Jomon settlement, sea surface temperatures during its zenith 5,000 years ago were roughly 2°C warmer than today; yet around 4,200 years ago, abrupt cooling destabilized the harvest of cultivated chestnuts that sustained the community. Unable to feed its population, the settlement was eventually abandoned. The fortunes of Jomon society rose and fell with the climate, and the long decline after the Middle Jomon peak was driven by environmental deterioration, dwindling yields, and resource depletion.

During the balmy Middle Jomon, when forest and marine bounty was plentiful, people adopted settled lives, forming substantial villages. Even while remaining foragers at their core, their growing numbers gave rise to settlements supporting hundreds of inhabitants, such as Sannai-Maruyama. In this era of abundance, the Jomon crafted pottery and dogu (土偶)—clay figurines—of extraordinary intricacy and diversity, bringing their culture into full flower.

Significantly, in northern Tohoku, where Jomon culture had prospered most, monumental stone circles (kanjo resseki, 環状列石) spanning thirty to forty meters across began appearing around 4,000 years ago in the Late Jomon—coinciding precisely with this demographic pressure.

Rather than belonging to a single tribe, these stone circles likely served as communal ritual grounds where neighboring clans gathered at fixed times of the year. By convening for nocturnal ceremonies, they eased psychological anxiety and forged collective solidarity.

Indeed, the distribution of stone circles in Tohoku coincides exactly with the areas of heaviest population concentration at the time. This geographic match bears out the hypothesis that stone circles were erected as a ritual solution to the unprecedented pressures generated by population growth.

It is a large wetland shell mound spanning the Jomon period from the incipient to the early phase (about 13,000 to 5,500 years ago), and has drawn attention as a precious site indispensable for knowing the whole of the Jomon. Excavations continued for a quarter century after its discovery in 1962 and brought a series of epoch-making finds that overturned the earlier picture of the Jomon people.

Because the site was preserved over a long time in a wet environment, organic remains that would ordinarily have rotted away, such as wood, plants, and seeds, survived in extremely good condition, the best in Japan, and more than 250,000 items have been recovered. Torihama showed in abundance the organic remains of the Jomon that had been so hard to find, and so we have been able to reconstruct, as a whole, the livelihood, environment, and culture of the period.

Eleven cedar dugouts have been found, two at Torihama and nine at the nearby Yuri site. They are not relics of a single time. Their dates range from about 6,300 to 2,700 years ago, which suggests that the Torihama and Yuri sites served as something like a port from which people set out onto the lake.

Astonishingly, from around the early Jomon the people here, when they tired of fishing the lake, passed from Lake Mikata through Suigetsu, Suga, and Kukushi out into the sea of Wakasa Bay and fished the open water. Their diet was very rich, and the shell mound shows they ate tuna, dolphin, and whale in quantity. This overturns the view that there was no technique for going far out, and shows that the Jomon were already catching, as a matter of course, fish as hard to take as tuna. The Japanese love of tuna begins in the Jomon.

The navigational skill of the Jomon people here served not only fishing but the exchange of information with other regions.

Look at a map of Japan, and Wakasa served as a crossroads, east and west, on the Sea of Japan side that was flourishing in the Jomon.

What matters is this. Because of the immigrants who came, Japan is easily seen as the final destination at the far eastern end, but the Jomon people of this place overturn that fixed idea.

Although inquiries based on this premise have been carried on for decades across many fields, it remains a great mystery on which no clear conclusion has yet been reached. While it is taken as self-evident that people began living in the Japanese archipelago roughly along these two paths, how that current itself unfolded is still unknown. Given the landforms of the day and lower sea levels, it is certainly plausible that on the northern route people could reach the Wakkanai area at the northern tip of Hokkaido directly from Sakhalin, or reach it by only a brief sea crossing. Yet if that were so, there ought to be cultural ties between the area around Sakhalin and northern Hokkaido—and almost no trace of them has yet been found.

On the other hand, another possibility that has drawn attention is an island-hopping route by way of the Kuril Islands. This is a route of crossing little by little by boat from island to island out of the Siberian side, eventually reaching the Shiretoko and Nemuro areas of Hokkaido—and interestingly enough, on this side, commonalities in Jomon culture have long been pointed out.

Since the Second World War, however, the Northern Territories issue between Japan and Russia has lain across this region; with the Japanese side and the Russian side each carrying out surveys in different eras, diplomatic constraints have made consistent investigation difficult, leaving the question unresolved. Bringing the full picture of this route to light will likely take a great deal of time yet, making the restoration of diplomatic ties between the two sides an urgent matter.

The word "Ainu" sometimes refers to a people and sometimes to a culture, and I feel it is all too often spoken of without distinguishing between the two.

This is a fundamental question: the history of Hokkaido begins to come into view when we carefully untangle how the word is used.

To begin with, the name "Ainu" only became common after the Meiji Restoration, and does not exist in Japanese records before that time. That is because "Ainu" is a name rooted in their own language, and was not in general use on the Japanese side.