Update: Explorers successfully voyage to Japan in primitive boat in bid to unlock an ancient mystery

Update, 10 July, 6:20 a.m.: A team of adventurers succeeded in paddling a primitive dug-out canoe across more than 200 kilometers of ocean to demonstrate how ancient humans may have reached the Ryukyu Islands scattered between Taiwan and Japan. “It was an unexpected big success,” says anthropologist Yousuke Kaifu of Japan's National Museum of Nature and Science in Tokyo. The five-person crew set out from Taiwan in the early afternoon on 7 July. Exhausted after a day and a half of paddling, the seafarers decided to rest on their second night at sea. As they slept, ocean currents carried them toward their target. “It was really lucky,” Kaifu says. They completed the trip just before noon on 9 July, after about 45 hours at sea. Drifting off course added 30 to 40 kilometers to the trip, Kaifu estimates. Whether paleolithic people really paddled across the ocean “is difficult to prove in a scientific way,” Kaifu says. But the experiment gives him the feeling that “that's the way our ancestors did it,” he says.

Here is our previous story from 2 July:

In the next week or so, five adventurers will attempt to paddle a primitive hand-hewn canoe across 200 kilometers of ocean in hopes of revealing how humans originally populated East China Sea islands. The 40-hour trip, from Taiwan to Yonaguni, the westernmost of Japan’s Okinawa Islands, is the culmination of a 6-year effort to experimentally determine what kinds of craft Paleolithic peoples may have built and used, and how they navigated over long ocean voyages.

The voyagers will cross from Taiwan to Yonaguni in Japan, (red arrow) allowing a strong current to pull them northward as they paddle eastward. Source: A source name here John Smith / Science 0 150 Km TAIWAN CHINA Philippine Sea East China Sea South China Sea Taiwan Strait Taitung Hualien Taichung Tainan Kaohsiung Keelung Pescadores Xiamen Ishigaki Yonaguni Taipei

Archaeological sites show humans first arrived in Japan more than 30,000 years ago. They likely reached the main islands from northeast Asia via a land bridge from Siberia and by crossing the straits in watercraft from the Korean Peninsula.

But how Paleolithic humans settled the Ryukyus, the present-day Okinawa Islands that stretch 1200 kilometers from Taiwan to Japan's Kyushu Island, “is really a big mystery,” says Yousuke Kaifu, an anthropologist at Japan's National Museum of Nature and Science in Tokyo who dreamed up the expedition. The “very difficult” sea voyages were undoubtedly made in boats built of materials that have not survived, he says. And sailing boats had not yet appeared, So Kaifu’s team has been building and testing watercraft that prehistoric seafarers might have paddled.

Yonaguni can be seen from Taroko Mountain in northeastern Taiwan. So ancient peoples presumably knew of the island, even though it can’t be seen from shore, Kaifu says. To show the Taiwan-to-Yonaguni crossing could have been done, Kaifu starting to plan the “holistic reenactment” voyage in 2013. The team first built boats made of bundled bulrushes, similar in design to reed boats used by prehistoric peoples around the world; and then bamboo rafts, relying on traditional techniques used by Taiwan’s Amis tribe. Short-distance trial runs showed these crafts were slow and that currents pulled them off-course. The team concluded they were not suitable for long-distance voyages.

For their full-scale trip, Kaifu’s team—all seasoned ocean kayakers—will be paddling a log boat or dugout canoe of a type found in China and Japan dating back 8000 years. The team used simple stone axes, modeled on Paleolithic era archaeological findings in Japan, to chop down a 1-meter-thick tree and then hew it into a 7-meter-long, 350-kilogram dugout. It proved lighter, more buoyant, and about 50% faster than the other craft. To emulate the ancients in other ways, the crew will not use modern navigational tools. Instead, the team includes a Maori man from New Zealand who can navigate by following the stars and judging winds and ocean swells.

Whatever happens, the results should be interpreted cautiously, says Helen Farr, an archaeologist at the University of Southampton in the United Kingdom. Sea level would have been about 100 meters lower than it is now, she notes, and that could have affected the routes chosen by voyagers, among other things. Still, she praises the experiment, saying that it could “inform our understanding” of the challenges of early seafaring—and the skills, technologies, and social organization required for such a journey.

Even failure might be informative, says Robin Dennell, an archaeologist at the University of Exeter in the United Kingdom who has studied the peopling of the Ryukyus. “It might show us how the islands were … not colonized,” he says, “and that might encourage a search for alternatives.” He also likes how the project is leading modern humans to “admire what people were able to do over 30,000 years ago.”

*Correction, 10 July, 9:45 a.m.: The map accompanying this story was updated to more accurately show the planned voyage route.

*Correction, 12 July, 11 a.m.: The update at the top of this story has been corrected to remove a reference to the paddlers losing their way, which was based on a misunderstanding between those in the canoe and the support crew. Yousuke Kaifu’s scientific speciality has also been updated.