A video about re-enacting a Stone Age voyage from Taiwan to the Ryukyu Islands of southern Japan, provided by the University of Tokyo.
Stone Age seafarers braved rough waters from Taiwan to Japan
About 30,000 years ago, ancient seafarers traveled from Taiwan to the Ryukyu Islands of southern Japan. They navigated through rough conditions with no landmarks or maps and had to cross one of the most powerful ocean currents in the world. Indeed, they could only rely on the sun, stars, ocean swells and their instincts to find their bearings. On June 26, 2025, scientists from Taiwan and Japan said they re-enacted that ancient voyage using a canoe made from replica tools of the period. In addition, they also used numerical simulations to study different scenarios for successfully undertaking such a challenging journey.
Yousuke Kaifu of the University of Tokyo led the studies. He said:
We initiated this project with simple questions: How did Paleolithic [Stone Age] people arrive at such remote islands as Okinawa? How difficult was their journey? And what tools and strategies did they use?
Archaeological evidence, such as remains and artifacts, can’t paint a full picture because the nature of the sea is that it washes such things away. So, we turned to the idea of experimental archaeology, in a similar vein to the Kon-Tiki expedition of 1947 by Norwegian explorer Thor Heyerdahl.
The researchers published two papers about their findings in the peer-reviewed journal Science Advances on June 25, 2025. One paper described a re-enactment of the Paleolithic voyage. Another paper detailed numerical simulations to identify conditions needed for a successful voyage.
Humans settled in southern Japan about 30,000 years ago
Modern humans first appeared in southern Japan, specifically the Ryukyu islands, about 35,000 to 30,000 years ago. They were early seafarers, likely traveling from Taiwan. To make that journey, they had to cross a formidable barrier, the Kuroshio, one of the most powerful ocean currents in the world.
There was an additional challenge, however. The southern Ryukyu Islands are small and low. Therefore, they are not visible from Taiwan and could not be used as navigational landmarks.
What vessels did Stone Age seafarers use?
There are no remains of the vessels used 30,000 years ago. Therefore, scientists tested some likely candidates: reed-bundled rafts and bamboo rafts. However, those rafts, despite being well-designed and carefully constructed, could not withstand the rough waters of the Kuroshio Current. The researchers also ruled out a sailing vessel because sails appeared much later in history, about 5,000 years ago in Egypt.
Next, they tried dugout canoes, built from Japanese cedar trunks and carved using replica Paleolithic stone tools. To be sure, after some testing, the researchers came up with a canoe that could withstand the rough waters of the Kuroshio Current.
Re-enacting an ancient voyage from 30,000 years ago
On July 7, 2019, five highly skilled canoe paddlers set out in a 25-foot dugout canoe from Wushibi in eastern Taiwan. They had no modern navigation aids, such as a GPS or compass. Instead, they depended on the sun, stars and swells to navigate in the open ocean. (For safety, they were monitored by a boat that also provided some food and water.)
Their destination was the small island of Yonaguni, a part of Japan’s Ryukyu Island group. The crew paddled 140 miles (225 km) from their starting point in Wushibi, Taiwan, to Yonaguni.
Later, about two hours into the trip, the water became choppy as they entered the Kuroshio Current. The crew had to constantly watch for large waves, because they had to steer directly toward them, to ride the waves and keep water from inundating the vessel. The crew exited the main Kuroshio Current about 17 hours after leaving Taiwan.
At night, when the sky was clear, the crew used the stars to find their bearings. Likewise, in the morning and evening, they used the sun to navigate. A detailed timeline of their grueling journey is available in the paper about the expedition.
In all, they spent 45 hours paddling to Yonaguni Island, arriving there on July 9, 2019.
Numerical simulations reconstruct possible ancient voyages
The 2019 re-enactment was a one-time experiment under specific weather and ocean conditions. It’s not sufficient, however, to understand how Stone Age seafarers traveled from Taiwan to the Ryukyu Islands.
So, what circumstances allowed them to successfully complete their journey? The researchers used numerical simulations to explore various travel scenarios. Likewise, they tested different seasons, departure locations and paddling strategies using modern and Paleolithic ocean conditions.
Ultimately, the simulations revealed that these ancient humans had a deep knowledge of seafaring strategy. For instance, they might have departed from northern Taiwan because it provided the best chances for completing their journey. They also knew about the Kuroshio Current, perhaps from fishing expeditions. Therefore, they paddled slightly southeast in their canoes to counteract the powerful northward current.
A one-way journey
In addition, simulations showed that once they entered the powerful northward Kuroshio Current, they could not paddle back to Taiwan.
Kaifu remarked:
We now know that these canoes are fast and durable enough to make the crossing, but that’s only half the story. Those male and female pioneers must have all been experienced paddlers with effective strategies and a strong will to explore the unknown. We do not think a return journey was possible. If you have a map and know the flow pattern of the Kuroshio, you can plan a return journey, but such things probably did not take place until much later in history.
Bottom line: Scientists re-enacted a Stone Age voyage from Taiwan to the Ryuku Islands of southern Japan using a canoe made from replica tools of that period. In addition, they also ran numerical simulations to study the conditions for successfully completing the journey.
Source: Traversing the Kuroshio: Paleolithic migration across one of the world’s strongest ocean currents
Source: Palaeolithic seafaring in East Asia: an experimental test of the dugout canoe hypothesis
Via University of Tokyo
Watch: SUGIME – Documentary film of the “Holistic reenactment project of voyages 30,000 years ago” (in Japanese with English subtitles)
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