Traversing the Kuroshio: Paleolithic migration across one of the world's strongest ocean currents

The maritime migration to the South Ryukyu Islands of southwestern Japan, which occurred approximately 30,000 years ago, was one of the most difficult sea crossings accomplished by the Late Pleistocene Homo sapiens. This study performs numerical simulations to investigate the conditions that were needed to cross between Taiwan and Yonaguni Island, where one of the world's strongest ocean currents, the Kuroshio, remains active. We combined simulations based on three ocean models with data from an actual experimental voyage conducted in 2019. The results showed that travel across this sea would have been possible on both the modern and Late Pleistocene oceans if a dugout canoe was used with a suitable departure place and paddling strategy. Recognizing the Kuroshio, paddling to counteract this current, and using high-level navigation were crucial to success. This suggests that the Paleolithic maritime expansion in the Western Pacific involved both advanced technologies and strategic challenges.