Latest news with #Kuroshio
Asahi Shimbun
25-07-2025
- Science
- Asahi Shimbun
Early humans likely navigated strong currents to reach Japan
Unlocking a 30,000-year-old mystery, scientists now believe they know how early humans successfully navigated the seas to migrate to Japanese islands. In 2019, a team of researchers in Japan demonstrated in an experiment that a crew of five in a dugout canoe could sail from Taiwan through one of the world's strongest currents to reach Yonagunijima island, Japan's westernmost island. In an update to the experiment, the team identified the route and timing that would have made such a voyage possible. The researchers reported that the crossing highly likely occurred during the Paleolithic Age if the starting point and direction of travel were altered based on simulations incorporating modern and prehistoric oceanic circulation patterns. Yousuke Kaifu, leader of the research project, said he believed that ancient humans living on the east coast of Taiwan were aware from fishing at sea of the powerful Kuroshio Current, which flows south to north between the two islands. In addition, these early seafarers knew that they would be swept away by the current if they ventured out too far. 'Among early humans were a group of experienced paddlers who were adept at rowing a dugout canoe,' said Kaifu, professor of human evolution and migration at the University of Tokyo's University Museum. 'They must have tackled the seafaring challenge with a strategy for handling the current, knowing that it is there and how it flows.' The study by Kaifu and other scientists from Ehime University, the Japan Agency for Marine-Earth Science Technology and other institutions was reported in the U.S. scientific journal Science Advances on June 25. OVERCOMING KUROSHIO CURRENT The ancestors of the Japanese are thought to have migrated via several routes. One route was from Taiwan and the Philippines to the Ryukyus, a chain of islands located between the main island of Kyushu and Taiwan. The remnants of artifacts and structures dating to 35,000 years ago have turned up in these islands. But how prehistoric mariners could navigate the open sea against the strong Kuroshio, which is also known as the Black Stream, was a major question. Kaifu's project, dubbed 'Holistic Reenactment Project of Voyages 30,000 Years Ago,' aimed at finding a plausible hypothesis. The project, organized by the National Museum of Nature and Science, Tokyo, began with building a vessel that the seafarers might have used. The team tested reed-bundled rafts and rafts made of bamboo and rattan between 2016 and 2018, but they were found to be too slow to negotiate the Kuroshio. In the third attempt, a non-sailing dugout canoe was built of a Japanese cedar tree with stone axes modeling after tools dating 30,000 years ago. A crew of five--four men and one woman, including sea kayaking guides--successfully traveled to Yonagunijima on the 7.5-meter-long canoe, paddling for about 200 kilometers from Taiwan in July 2019. In the 45-hour journey, the crew navigated through using the sun, stars and prevailing winds. While the 2019 crossing was successful, it was a one-off event. And there were some points researchers needed to consider before concluding that it was still feasible for seafarers in prehistoric times to cross the seas, given the differences in ocean and climate conditions between then and now. SCENARIO REPLICATES LONG-AGO VOYAGE In the latest experiment, the crew departed from a location some 140 km southwest of Yonagunijima to avoid the full strength of the current, which flows at a speed of 1-2 meters per second. But there was an issue with this selection: Yonagunijima was nowhere to be seen from the top of the mountains near the departure site, likely providing no motiviation for braving the ocean in search of new lands. In addition, research showed that 30,000 years ago, sea levels were lower than today and the Kuroshio flowed in a different pattern in the Paleolithic Age. Kaifu's team studied various scenarios for virtual voyages by simulating the current based on modern and prehistoric ocean models. In the simulation, the departure point was moved to a site more than 100 km north from the experiment to make Yonagunijima visible from nearby mountains on a fine day, the adjustment meant to make intentional seafaring likely. As a result, the Kuroshio currents around the new starting point were estimated to flow 10-20 percent faster than in the experiment due to a change in the sea floor topography and flowed slightly eastward. If mariners headed east straight toward Yonagunijima, they would have been pushed off course by the current and failed to spot the island, according to the study. But the researchers also showed that they could have reached the island in 28.6 hours, about 17 hours shorter than in the experiment, if they took into consideration the Kuroshio's flow pattern, paddling to the southeast. Even if the mariners traveled slower than the crew did in the experiment, it was nearly certain that they could have found the targeted island, the findings also showed. In wrapping up the project, Kaifu expressed awe for the ancient seafarers who undertook the perilous journey. 'We understand from our failed attempts that the sea crossing was a formidable undertaking for them, considering they only had primitive technology,' he said. 'The dugout canoe must have been a cutting-edge product at the time, but they still needed to continue to work extremely hard to maneuver it and successfully pull off the voyage. I just find it amazing.' A short documentary and videos of the project are available at the Holistic Reenactment Project of Voyages 30,000 Years Ago section of the website for the National Museum of Nature and Science, Tokyo, at（ ） PHOTOS 1 A five-member crew sets off from eastern Taiwan on July 7, 2019, in a dugout canoe to cross the open sea to reach Yonagunijima island in Japan in a project aimed to uncover how ancient mariners migrated 30,000 years ago. (Provided by Yousuke Kaifu) 2 A view of the sea toward the direction of Japan's Yonagunijima island from Mount Liwu in Taiwan. The powerful Kuroshio Current flows offshore. (Provided by Yousuke Kaifu) 3 A stone axe with a handle was made to build a canoe used in the 2019 experimental seafaring. The axe was modeled after tools from the Paleolithic Age. (Provided by Yousuke Kaifu) 4 A Japanese cedar tree measuring 1 meter across was felled with a wooden axe to build a dugout canoe. (Provided by Yousuke Kaifu) 5 Yosuke Kaifu, left, professor of human evolution and migration at the University of Tokyo's University Museum, Yu-Lin Chang, center, deputy senior scientist with the Japan Agency for Marine-Earth Science Technology, and Xinyu Guo, professor of marine environmental studies at Ehime University, at a news conference in Tokyo in June (Rintaro Sakurai)
Observer
29-06-2025
- Science
- Observer
With a primitive canoe, scientists replicate prehistoric seafaring
Our species arose in Africa roughly 300,000 years ago and later trekked worldwide, eventually reaching some of Earth's most remote places. In doing so, our ancestors surmounted geographic barriers including treacherous ocean expanses. But how did they do that with only rudimentary technology available to them? Scientists now have undertaken an experimental voyage across a stretch of the East China Sea, paddling from Ushibi in eastern Taiwan to Japan's Yonaguni Island in a dugout canoe to demonstrate how such a trip may have been accomplished some 30,000 years ago as people spread to various Pacific Islands. The researchers simulated methods Paleolithic people would have used and employed replicas of tools from that prehistoric time period such as an axe and a cutting implement called an adze in fashioning the 25-foot-long (7.5-meter) canoe, named Sugime, from a Japanese cedar tree chopped down at Japan's Noto Peninsula. A crew of four men and one woman paddled the canoe on a voyage lasting more than 45 hours, traveling roughly 140 miles (225 km) across the open sea and battling one of the world's strongest ocean currents, the Kuroshio. The crew endured extreme fatigue and took a break for several hours while the canoe drifted at sea, but managed to complete a safe crossing to Yonaguni. Just as prehistoric people would have, the voyagers navigated by the sun and stars, as well as the direction of the ocean swells, though for safety's sake they were accompanied by two escort craft. Yonaguni is part of the Ryukyu chain of islands stretching from Kyushu, the southernmost of Japan's four main islands, down to Taiwan. Researcher Kunihiro Amemiya uses a period-accurate axe to chop down a Japanese cedar tree in Noto Peninsula, Japan, to make a dugout canoe for a crossing across a region of the East China Sea from Taiwan to Yonaguni Island, in this handout image released on June 25, 2025. Yousuke Kaifu/Handout via REUTERS THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. NO RESALES. NO ARCHIVES The researchers previously failed with attempted crossings using reed rafts and then bamboo rafts, finding that they were too slow, insufficiently durable and unable to overcome the strong ocean current. "Through the project with many failures, we have learned the difficulties of crossing the ocean, and this experience gave us a deep respect for our Paleolithic ancestors," said University of Tokyo anthropologist Yousuke Kaifu, lead author of the study published on Wednesday in the journal Science Advances. "We found that the Paleolithic people could cross the sea with the strong ocean current if they had dugout canoes and were skillful, experienced paddlers and navigators. They had to face the risk of being drifted by the strong ocean current and the possibility that they would never be able to come back to their homeland," added Kaifu, who was aboard one of the escort boats. Archeological evidence indicates that people approximately 30,000 years ago first crossed from Taiwan to some of the Ryukyu islands, which include Okinawa. But scientists had puzzled over how they could do this with the rudimentary technology of the time - no maps, no metal tools and only primitive vessels. And the Kuroshio current, comparable in strength to the Gulf Stream off Mexico, presented a particular challenge. The research was in the vein of the famous 1947 Kon-Tiki expedition in which Norwegian explorer Thor Heyerdahl carried out a much longer journey by raft from South America across the Pacific to the Polynesian islands. Heyerdahl aimed to show how prehistoric people from the Americas could have colonized Polynesia. "His theory is now countered by a series of pieces of evidence, but it was a great trial at the time. Compared to the time of the Kon-Tiki, we have more archeological and other evidence to build realistic models" of prehistoric voyages, Kaifu said. The researchers in a companion study published in the same journal used simulations of sea conditions between Taiwan and Yonaguni 30,000 years ago to examine whether such a crossing was attainable at a time when the Kuroshio was even more powerful than today. "As our paleo-ocean model simulation showed, crossing the Kuroshio was possible in ancient times, so I believe they achieved it," said physical oceanographer and study lead author Yu-Lin Chang of the Japan Agency for Marine-Earth Science and Technology. "However, ocean conditions were highly variable. Thus, ancient people may have encountered unpredictable weather conditions during their journey, which could have led to failure," Chang added. —Reuters
Yomiuri Shimbun
29-06-2025
- Science
- Yomiuri Shimbun
Humans May Have Crossed from Taiwan to Yonaguni 30,000 Years Ago; Strategically Navigated Currents Following Sun, Stars
It is possible Paleolithic humans in a rowboat were able to cross from Taiwan to Yonaguni Island, Okinawa Prefecture, 30,000 years ago, according to an analysis by a research team from the University of Tokyo and other organizations. The team conducted an experimental voyage using a reproduction wooden boat and analyzed ocean currents using a supercomputer. As a result, they found travel across the sea would have been possible, depending on the skill of those in the boat. The result was published in the scientific journal Science Advances. Japanese ancestors are thought to have arrived from the continent via three routes: Hokkaido, Tsushima Island and the Ryukyu Islands. Arrival via the Ryukyu Islands route is believed to have taken place around 35,000 to 30,000 years ago during the late Paleolithic period. However, as Taiwan and Yonaguni Island are separated by the Kuroshio current, a strong ocean current with a speed of 1 to 2 meters per second, how they crossed the sea had been a mystery. In 2019, a research team from the National Museum of Nature and Science and other institutions conducted a 225-kilometer experimental voyage in a wooden boat made from a hollowed-out cedar tree. Five paddlers departed from the east coast of Taiwan and reached Yonaguni Island in 45 hours, navigating based on the position of the sun and stars. Later, the Japan Agency for Marine-Earth Science and Technology and others used a supercomputer to perform numerical simulations to investigate the conditions 30,000 years ago and found the Kuroshio current was 10%-20% faster than today. Based on the results of the experimental voyage, they conducted a hypothetical test with the boat having a maximum speed of 1.08 meters per second, and, taking into account the flow of the current, found the probability of a successful voyage would increase if the boat was paddled at an angle slightly against the Kuroshio current. 'We have discovered our ancestors were strategic explorers who understood the effects of ocean currents and used their skillful navigation techniques to cross the sea,' said University of Tokyo Prof. Yosuke Kaifu, head of the research team.
TimesLIVE
26-06-2025
- Science
- TimesLIVE
With a primitive canoe, scientists replicate prehistoric seafaring
Our species arose in Africa roughly 300,000 years ago and later trekked worldwide, eventually reaching some of Earth's most remote places. In doing so, our ancestors surmounted geographic barriers including treacherous ocean expanses. But how did they do that with only rudimentary technology available to them? Scientists now have undertaken an experimental voyage across a stretch of the East China Sea, paddling from Ushibi in eastern Taiwan to Japan's Yonaguni Island in a dugout canoe to demonstrate how such a trip may have been accomplished some 30,000 years ago as people spread to various Pacific Islands. The researchers simulated methods Paleolithic people would have used and employed replicas of tools from that prehistoric time period such as an axe and a cutting implement called an adze in fashioning the 7.5-metre-long canoe, named Sugime, from a Japanese cedar tree chopped down at Japan's Noto Peninsula. A crew of four men and one woman paddled the canoe on a voyage lasting more than 45 hours, travelling roughly 225km across the open sea and battling one of the world's strongest ocean currents, the Kuroshio. The crew endured extreme fatigue and took a break for several hours while the canoe drifted at sea, but managed to complete a safe crossing to Yonaguni.
Deccan Herald
26-06-2025
- Science
- Deccan Herald
Scientists retrace 30,000-year-old sea voyage, in a hollowed-out log
In 2017, with the support of Taiwan's National Museum of Prehistory, the scientists toyed with rafts made of bamboo and rattan. A prototype was durable but, as was the case with the reed crafts, not fast enough to negotiate the Kuroshio. A second, lighter version was prone to cracking and did not last long in the high seas.
