Japan today has a population of 126 million inhabitants. Ethnic minorities are few: primarily Koreans (600,000, from both North and South) and also Chinese from Taiwan.

As for the exact origins of the Japanese people, they remain shrouded in mystery.

Beginning with the origins of their language, which are poorly understood. It shares similarities with the Altaic language family (Turkish, Mongolian, Tungusic, Korean) in terms of syntax, phonology, and semantics. Semantically, it could also bear resemblance to Malayo-Polynesian languages. In short, it doesn't truly relate to any other linguistic family, and this specificity suggests it has very ancient origins. It is believed that by the 3rd century BC, inhabitants already spoke a language ancestral to modern Japanese.

As for research into the ethnic origins of the people, it was long hindered by official doctrine that advocated the absolute homogeneity of the Japanese people.

For a time, it was thought that the Ainu were the original population of Japan. They are a very ancient and mysterious community, of which a small population (20,000) still survives in northern Japan, in Hokkaido.

Long regarded as a barbaric people, they first distinguished themselves physically in that they resembled Caucasians more closely, but also culturally. They began practicing agriculture around the 13th century, developed an oral literature, and a culture intimately tied to nature upon which they depended heavily (the veneration of animals was central to their life and craftsmanship). Pressured toward assimilation into the modern world, few still speak their language and their civilization is on the verge of disappearing.

In any case, it is now established that the Ainu were never the original and dominant population of Japan, as certain older theories suggested they had been decimated by invaders from the continent. Indeed, Neolithic skeletons show that inhabitants were then closer to present-day Japanese than to the Ainu.

Japan has also experienced influxes of new populations from the continent: China, Korea, Siberia, Mongolia. However, due to the country's island geography, these arrivals were never massive.

Between the 3rd century BC and the 3rd century AD (Yayoi period), an increase in the height of discovered skeletons is evident: was this due to an invasion of populations from northern Asia (Mongolic)? Or to improved nutrition benefiting from nascent rice cultivation? No evidence determines this.

In conclusion, one can say that no one knows the origins of the Japanese people, nor those of their language, and one is left with speculation. Certainly it is not a homogeneous people, but there have been no significant population influxes in recorded history (lacking knowledge of prehistory).

Evidence of its isolation: Japan only acquired certain continental technologies late in its history. For example, bronze and writing, known since 1500 BC in China, did not appear in Japan until around the beginning of the Common Era!