Excavation at the Kanmuri site complex in Hatsukaichi, Hiroshima Prefecture — September 2025.
When and how did modern humans, Homo sapiens, first reach the Japanese archipelago? Recent excavations of stone tools have begun to answer this long-standing question.
After leaving Africa, early humans spread eastward across Eurasia along two paths: a northern route and a southern route. Stone tools discovered along both routes share strikingly similar features with artifacts found in Nagano and Hiroshima Prefectures, dating back more than 40,000 years. These finds are drawing attention as some of the earliest evidence of human presence in Japan.
Evidence from the Late Paleolithic
In Japan, clear evidence of human activity appears from around 38,000 years ago, during the Late Paleolithic. To better understand this era, a team led by Sadakatsu Kunitake, senior researcher at the Nara National Research Institute for Cultural Properties, began excavating the Kosakayama site in Saku City, Nagano Prefecture in 2020. The site sits at about 1,100 meters (3,610 ft) above sea level.
The team unearthed numerous stone tools, including large blades over 10 centimeters (3.9 in) long with sharp edges and small razor-like bladelets. Radiocarbon dating placed them at around 36,800 years old.
Looking for comparable examples, researchers then turned to the Kanmuri site in Hatsukaichi, Hiroshima Prefecture, another elevated location at about 800 meters where high-quality stone material is found nearby. Excavations there in 2024 uncovered pointed tools with sharp tips dating back roughly 42,300 years, pushing the finds into the Middle Paleolithic.
These artifacts are considered among the most credible finds in the ongoing debate over the archipelago's oldest stone tools, particularly in the wake of Japan's 2000 Paleolithic fabrication scandal, in which an amateur archaeologist was found to have faked discoveries.
Reconsidering Human Migration
Based on these two findings, Kunitake explains: "We now have materials that make it possible to study when modern humans began living in the Japanese archipelago on the same basis as research on the Eurasian continent."
Modern humans are thought to have emerged in Africa around 200,000 years ago before spreading across the globe. In Eurasia, they likely moved eastward along two routes divided by the Himalayas.
According to Kunitake, blade-based stone tool assemblages dating from 50,000 to 40,000 years ago have been found in Central Asia, southern Russia, and Mongolia along the northern route. These tools are "almost indistinguishable" from those unearthed at the Kosakayama site.
The pointed tools from the Kanmuri site tell a different story. Their edges are shaped like saw teeth, a feature that closely matches serrated-edge stone tool assemblages from Middle Paleolithic China, pointing to a southern lineage that passed through Southeast Asia.
Taken together, the evidence suggests that humans traveling both the northern and southern routes may have ultimately converged on the Japanese archipelago as a shared destination.
Tools Shaped by Their Environments
Although stone tools were used for multiple purposes, the environments along the routes differed.
- Along the northern route, with its cold climates and grasslands, tools may have been suited to hunting and butchering large herbivores.
- Along the southern route, with more forests, tools may have been better adapted for capturing small animals and gathering plants.
Excavations at the Kanmuri site will continue. Researchers are particularly interested in whether blade tools similar to those at Kosakayama will also be found there — potentially confirming the arrival of both migration routes at the same location.
Further dating analysis is underway, and the team aims to present results at the 2027 annual meeting of the Japanese Archaeological Association.
Tsugifumi Fujino, professor emeritus of prehistoric archaeology at Hiroshima University, said: "Researchers in Paleolithic archaeology experienced the fabrication scandal. As new findings emerge, the debate will deepen, but the evidence will be assessed cautiously."
The Paleolithic Period
The Paleolithic refers to the era when humans made stone tools by knapping and lived by hunting and gathering. It stretches from about 2.5 million years ago to around 12,000 years ago, when a warmer climate brought the advent of pottery and agriculture.
The period is divided into Early, Middle, and Late Paleolithic based on the characteristics of stone tools, though even older tools have been reported.
In Japan, most discoveries belong to the Late Paleolithic, from which large numbers of stone tools have been recovered. Pottery appeared relatively early in Japan compared to the rest of the world, and by around 16,000 to 14,000 years ago, the region had transitioned into the Jomon period.
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(Read the article in Japanese.)
Author: The Sankei Shimbun
