structural:summarization, structural:expansion
Incipient and Initial Jōmon (13,750–5,000 BC)

Traces of Paleolithic culture, mainly stone tools, occur in Japan from around 30,000 BC onwards. The earliest "Incipient Jōmon" phase began while Japan was still linked to continental Asia as a narrow peninsula. As the glaciers melted following the end of the last glacial period (approximately 12,000 BC), sea levels rose, separating the Japanese archipelago from the Asian mainland; the closest point (in Kyushu) about 190 km (120 mi) from the Korean Peninsula is near enough to be intermittently influenced by continental developments, but far enough removed for the peoples of the Japanese islands to develop independently. The main connection between the Japanese archipelago and Mainland Asia was through the Korean Peninsula to Kyushu and Honshu. In addition, Luzon, Taiwan, Ryukyu, and Kyushu constitute a continuous chain of islands, connecting the Jōmon with Southeast Asia, while Honshu, Hokkaido and Sakhalin connected the Jōmon with Siberia.

Within the archipelago, the vegetation was transformed by the end of the Ice Age. In southwestern Honshu, Shikoku, and Kyushu, broadleaf evergreen trees dominated the forests, whereas broadleaf deciduous trees and conifers were common in northeastern Honshu and southern Hokkaido. Many native tree species, such as beeches, buckeyes, chestnuts, and oaks produced edible nuts and acorns. These provided substantial sources of food for both humans and animals.

In the northeast, the plentiful marine life carried south by the Oyashio Current, especially salmon, was another major food source. Settlements along both the Sea of Japan and the Pacific Ocean subsisted on immense amounts of shellfish, leaving distinctive middens (mounds of discarded shells and other refuse) that are now prized sources of information for archaeologists. Other food sources meriting special mention include Sika deer, wild boar (with possible wild-pig management), wild plants such as yam -like tubers, and freshwater fish. Supported by the highly productive deciduous forests and an abundance of seafood, the population was concentrated in Honshu and Kyushu, but Jōmon sites range from Hokkaido to the Ryukyu Islands. Tigers once existed in the Japanese archipelago, but they became extinct in prehistoric times.