In the Japanese archipelago and contemporary nation of Japan, the Japanese people are an ethnic group that comprises 98.1 percent of the country's population. Japan is home to around 129 million individuals of Japanese heritage worldwide, with approximately 125 million of them residing in the country of Japan. Nikkeijin, the Japanese diaspora, refers to people of Japanese ancestry who reside outside of Japan and are of Japanese descent. The phrase "ethnic Japanese" is used to refer to persons from the Japanese mainland, especially the Yamato ethnic group. The Japanese people are one of the world's biggest ethnic groupings, with a population of over 100 million people.
In the Paleolithic era, between 39,000 and 21,000 years ago, Stone Age humans lived on the islands of the Japanese archipelago, according to archaeological data. At the time, Japan was linked to mainland Asia by at least one land bridge, and nomadic hunter-gatherers made their way over to Japan from the mainland. In Japan, archaeologists have discovered flint tools and bone objects from this time period.
Arai Hakuseki proposed in the 18th century that the ancient stone tools found in Japan were left behind by the Shukushin, a mythical race. The Ainu people were believed to be indigenous to northern Japan by Philipp Franz von Siebold in the latter nineteenth century. Based on his 1906 study into the Ryukyuan languages, Iha Fuy proposed that Japanese and Ryukyuan people have a same ethnic origin. For example, Torii Ryz believed that Yamato people used Yayoi pottery whereas Ainu people utilised Jmon pottery during the Taish era.
Japanese historians Kotondo Hasebe and Hisashi Suzuki asserted after World War II that the roots of the Japanese people did not lie with arrivals during the Yayoi era (300 BCE – 300 CE), but rather with individuals during the Jmon period. But in 1984, Kazuro Hanihara proposed a new racial mixing hypothesis, which he followed up with a "dual structure model" in 1991. The origins of current Japanese lineages, according to Hanihara, may be traced back to the Jmon people, who arrived in the Japanese archipelago around Paleolithic periods. This was followed by a second wave of immigration, this time from East Asia, which occurred during the Yayoi era (300 BC). This group of visitors first arrived in Japan during the Yayoi era, after a period of population increase in Neolithic times. Consequently, hunter gatherers were displaced in the island areas of Kyushu, Shikoku, and southern Honsh, but they did not replace them on the outlying islands of Okinawa and Hokkaido, and the Ryukyuan and Ainu people exhibit a mixture of features. According to Mark J. Hudson, the core ethnic picture of the Japanese people was physiologically and linguistically developed between 400 BCE and 1,200 CE, according to his research. Most scholars agree that modern Japanese people descended from a combination of Yayoi rice farmers and numerous Jmon era ethnic groups, which is the most widely accepted explanation at the moment.