It was once believed that “Japan had no Paleolithic period.” This belief was overturned by the discovery of the Iwakujuku Site in 1946. Let us examine the story of how one amateur researcher rewrote Japanese history.
Basic Knowledge
Iwakujuku Site is a Paleolithic site in Kasakake Town, Midori City, Gunma Prefecture. In 1946, a young man named Tadahiro Aizawa, who sold natto and goods as a peddler, discovered chipped stone tools in the Kanto Loam Layer (red soil).
At that time, the Kanto Loam Layer was considered a stratum made of deposited volcanic ash from a period when humans could not live there. However, Aizawa’s discovery led to an excavation by Meiji University in 1949, and many chipped stone tools were unearthed from the Kanto Loam Layer. This scientifically proved that Japan also had a Paleolithic period.
Afterward, Paleolithic sites were discovered one after another throughout Japan, and about 10,000 Paleolithic sites are known today.
Tadahiro Aizawa Amateur archaeologist and discoverer of the Iwakujuku Site (1946)
Iwakujuku Site (Gunma Prefecture) Japan’s first Paleolithic site
Lake Nojiri Site (Nagano Prefecture) Site where Naumann elephant and giant deer fossils and stone tools were unearthed
Shirataki Site (Hokkaido) Site of high-quality obsidian and microblades
Kanto Loam Layer Red soil layer originating from volcanic ash and containing Paleolithic tools
Further Study (Background and Impact)
Before the discovery of the Iwakujuku Site, Japanese history textbooks began with the Jomon period. This was because the geological difference between Europe, where Paleolithic tools were found in “strata carved by glaciers,” and Japan, where they were found in “red volcanic ash soil,” caused researchers to doubt the existence of Paleolithic tools in Japan.
Tadahiro Aizawa was not a scholar. He was a young man who studied archaeology independently between his peddling trips. He brought stone tools he had collected from the red soil to researchers in Tokyo, eventually leading to a full-scale investigation by Sokai Sugihara and others from Meiji University.
This discovery is still introduced in many books and textbooks as a symbolic event showing that “even an amateur can change history.” At the Lake Nojiri Site in Nagano Prefecture, stone tools were found together with Naumann elephant fossils, providing direct evidence that humans hunted large animals.
- 1946: Tadahiro Aizawa discovered chipped stone tools at the Iwakujuku Site in Gunma Prefecture
- 1949: Full-scale excavation by Meiji University → proof of the Paleolithic period in Japan
- Kanto Loam Layer = red soil from volcanic ash containing Paleolithic tools
- Lake Nojiri Site in Nagano Prefecture = Naumann elephant fossils + stone tools
- Shirataki Site in Hokkaido = obsidian-producing area
- Tadahiro Aizawa rewrote Japanese history as an amateur researcher
Points of Caution (Easily Confused)
① The Iwakujuku Site is in Gunma Prefecture, while the Lake Nojiri Site is in Nagano Prefecture. Do not confuse the prefectures. ② The stratum where “Paleolithic tools” were unearthed is the “Kanto Loam Layer,” or red soil. Remember that it originated from volcanic ash. ③ Tadahiro Aizawa was an amateur, not a scholar. Meiji University conducted the excavation itself. ④ In 2000, the “Paleolithic fabrication incident” involving forged tools by Shinichi Fujimura came to light, greatly shaking research on Japan’s Paleolithic period. However, the discovery of the Iwakujuku Site itself is genuine.
Practice
- State the discoverer, year of discovery, and location of the Iwakujuku Site.
- Explain what kind of stratum the Kanto Loam Layer is.
- Give the name of the site in Nagano Prefecture where Naumann elephant fossils and stone tools were unearthed.