Hunter-gatherers first arrived in Japan during the Paleolithic period, around 38-40,000 years ago.^[1] Due to Japan's acidic soils, which are not conducive to fossilization, little physical evidence of their presence remains. However, unique edge-ground axes dated to over 30,000 years ago suggest the arrival of the first Homo sapiens in the archipelago.^[4] Early humans are believed to have reached Japan by sea, using watercraft.^[5] Evidence of human habitation has been dated to specific sites such as 32,000 years ago in Okinawa's Yamashita Cave^[6] and 20,000 years ago in Ishigaki Island's Shiraho Saonetabaru Cave.^[7]