When Western archaeologists tell the story of how early humans spread across Asia, the Japanese archipelago typically appears as a footnote — if it appears at all. A new commentary in Nature Communications by Robin Dennell of the University of Exeter argues that this neglect is a major oversight. Japan, Dennell contends, has one of the richest and best-dated Palaeolithic records in the world, with features that challenge several fundamental assumptions about early human capabilities.
“Japan deserves more attention than it has so far received in Western narratives about the expansion of humans across Asia,” Dennell writes. “It has over 10,000 Palaeolithic sites, many of which are well-dated, and provides excellent examples of Pleistocene seafaring and long-distance exchange networks.”
Three phases, one rich record
The Japanese Palaeolithic is divided into three well-dated phases. The Early Upper Palaeolithic begins roughly 38,000 years ago, when the first humans crossed the Tsushima Strait from the Korean peninsula — a crossing made easier during glacial periods when sea levels dropped and the strait narrowed to roughly 20 km (12 miles). The Middle Upper Palaeolithic begins around 29,000 years ago and the Late Upper Palaeolithic from roughly 25,000 to 16,000 years ago.
Each phase shows distinctive tool technologies. Trapezoids — hafted projectile points, possibly among the earliest evidence of bow-and-arrow technology in East Asia — appear throughout. Ground-edge axes, found in Japan and Australia but virtually nowhere else in Eurasia, appear in the earliest layers. And pit traps — barrel-shaped pits roughly one metre deep and two metres wide, dug in rows along hillsides for driving game — are unique to Japan. The oldest known pit traps, at the Tachikiri site on Tanegashima Island, date to approximately 35,000 years ago.
Seafaring and obsidian exchange
Japan’s colonisation required sea crossings from the Korean peninsula, but the obsidian exchange networks that followed are even more impressive. Japan has over 70 known obsidian sources, and more than 80,000 analysed items document a network that by 38,000 years ago was moving obsidian from Kozushima Island, 45 km (28 miles) off the coast of Honshu — a six- to seven-hour voyage one way. Even more striking, obsidian from Koshidake in Kyushu was transported across the Tsushima Strait to the Korean peninsula, a distance of 350 km (217 miles).
The colonisation of the Ryukyu Islands was arguably the most impressive feat. The Kuroshio Current, one of the world’s strongest ocean currents, made return voyages essentially impossible. The likely route ran from Taiwan to Yonaguni (105 km (65 miles)), then island-hopping through Iriomote, Miyako, and finally to Okinawa, a 220-km (137-mile) open-water crossing. Okinawa was colonised by roughly 36,000 years ago.
Earliest animal translocation
At Sakitari Cave on Okinawa, layer II — dated to between 19,635 and 23,425 calibrated years before present — contained bones of wild pig (Sus scrofa). These animals were not native to Okinawa. Dennell argues this represents deliberate translocation by humans, possibly the earliest known example of humans intentionally moving an animal to a new environment.
A stepping stone to the Americas
Dennell also raises the possibility that Japan may have been a starting point for the colonisation of the Americas. The PalaeoSakhalin-Hokkaido-Kurile landmass was connected to the Siberian mainland during glacial periods. From there, a route along the Kurile and Aleutian Islands would have connected to the North American coast, following the “Kelp Highway” of rich marine resources. The Cooper’s Ferry site in Idaho, dated to between 16,560 and 15,280 years ago, predates the opening of the ice-free corridor, suggesting a coastal migration route — and Japan sits at the western end of that route.
Source
- Dennell R. “The Japanese Palaeolithic deserves more attention in Western narratives about human expansion across Asia.” Nature Communications 17:6387, 2026. DOI: 10.1038/s41467-026-74116-7