^ note: The population of naturalized Japanese people and their descendants is unknown. Only the number of the permanent residents with Japanese nationality is shown.
The Japanese people(日本人,Nihonjin?) are an ethnic group native to Japan. Japanese make up 98.5% of the total population of their country. Worldwide, approximately 130 million people are of Japanese descent; of these, approximately 127 million are residents of Japan. People of Japanese ancestry who live in other countries are referred to as nikkeijin(日系人?). The term ethnic Japanese may also be used in some contexts to refer to a locus of ethnic groups including the Yamato, Ainu, and Ryukyuan people.
Japanese religion has traditionally been syncretic in nature, combining elements of Buddhism and Shinto. Shinto, a polytheistic religion with no book of religious canon, is Japan's native religion. Shinto was one of the traditional grounds for the right to the throne of the Japanese imperial family, and was codified as the state religion in 1868 (State Shinto was abolished by the American occupation in 1945). Mahayana Buddhism came to Japan in the sixth century and evolved into many different sects. Today the largest form of Buddhism among Japanese people is the Jōdo Shinshū sect founded by Shinran.
Most Japanese people (84% to 96%) profess to believe in both Shinto and Buddhism. The Japanese people's religion functions mostly as a foundation for mythology, traditions, and neighborhood activities, rather than as the single source of moral guidelines for one's life.
Decorative arts in Japan date back to prehistoric times. Jōmon pottery includes examples with elaborate ornamentation. In the Yayoi period, artisans produced mirrors, spears, and ceremonial bells known as dōtaku. Later burial mounds, or kofun, preserve characteristic clay haniwa, as well as wall paintings.
Beginning in the Nara period, painting, calligraphy, and sculpture flourished under strong Confucian and Buddhist influences from China. Among the architectural achievements of this period are the Hōryū-ji and the Yakushi-ji, two Buddhist temples in Nara Prefecture. After the cessation of official relations with the Tang Dynasty in the ninth century, Japanese art and architecture gradually became less influenced by China. Extravagant art and clothing was commissioned by nobles to decorate their court, and although the aristocracy was quite limited in size and power, many of these pieces are still extant. After the Todai-ji was attacked and burned during the Gempei War, a special office of restoration was founded, and the Todai-ji became an important artistic center. The leading masters of the time were Unkei and Kaikei.
In theater, Noh is a traditional, spare dramatic form that developed in tandem with kyōgen farce. In stark contrast to the restrained refinement of noh, kabuki, an "explosion of color," uses every possible stage trick for dramatic effect. Plays include sensational events such as suicides, and many such works were performed in both kabuki and bunraku puppet theaters.
Since the Meiji Restoration, Japan has absorbed elements of Western culture. Its modern decorative, practical, and performing arts works span a spectrum ranging from the traditions of Japan to purely Western modes. Products of popular culture, including J-pop, manga, and anime have found audiences around the world.
A common origin of Japanese has been proposed by a number of scholars since Arai Hakuseki first brought up the theory and Fujii Sadamoto, a pioneer of modern archeology in Japan, also treated the issue in 1781. But after the end of World War II, Kotondo Hasebe and Hisashi Suzuki claimed that the origin of Japanese people was not the newcomers in the Yayoi period (300 BCE – 300 CE) but the people in the Jōmon period.
However, Kazuro Hanihara announced a new racial admixture theory in 1984. Hanihara also announced the theory "dual structure model" in English in 1991. According to Hanihara, modern Japanese lineages began with Jōmon people, who moved into the Japanese archipelago during Paleolithic times from their homeland in southeast Asia. Hanihara believed that there was a second wave of immigrants, from northeast Asia to Japan from the Yayoi period. Following a population expansion in Neolithic times, these newcomers then found their way to the Japanese archipelago sometime during the Yayoi period. As a result, miscegenation was rife in the island regions of Kyūshū, Shikoku, and Honshū, but did not prevail in the outlying islands of Okinawa and Hokkaidō, and the Ryukyuan and Ainu people continued to dominate there. Mark J. Hudson claimed that the main ethnic image of Japanese people was biologically and linguistically formed from 400 BCE to 1,200 CE.
Masatoshi Nei opposed the "dual structure model" and alleged that the genetic distance data show that the Japanese people originated in northeast Asia, moving to Japan perhaps more than thirty thousand years ago.
On the other hand, research in October 2009 by the National Museum of Nature and Scienceet al. concluded that the Minatogawa Man, who was found in Okinawa and was regarded as evidence that Jōmon people came to Japan via the southern route, had a slender face unlike the Jōmon. Hiroto Takamiya of the Sapporo University suggested that the people of Kyushu immigrated to Okinawa between the 10th and 12th centuries CE.
A 2011 study by Sean Lee and Toshikazu Hasegawa reported that a common origin of Japonic languages had originated around 2,182 years before present.
Glacier cover in Japan at the height of the last glaciation about 20,000 years ago
Currently, the most well-regarded theory is that present-day Japanese are descendants of both the indigenous Jōmon people and the immigrant Yayoi people. The origins of the Jōmon and Yayoi people have often been a subject of dispute, and a recent Japanese publisher has divided the potential routes of the people living on the Japanese archipelago as follows:
Aboriginals that have been living in Japan for more than 10,000 years. (Without geographic distinction, which means, the group of people living in islands from Hokkaido to Okinawa may all be considered to be Aboriginals in this case.)
Some of the world's oldest known pottery pieces were developed by the Jōmon people in the Upper Paleolithic period, 14th millennium BC. The name, "Jōmon" (縄文 Jōmon), which means "cord-impressed pattern", comes from the characteristic markings found on the pottery. The Jōmon people were Mesolithic hunter-gatherers, though at least one middle to late Jōmon site (Minami Mizote (南溝手?), ca. 1200–1000 BC) had a primitive rice-growing agriculture. They relied primarily on fish for protein. It is believed that the Jōmon had very likely migrated from North Asia or Central Asia and became the Ainu of today. Research suggests that the Ainu retain a certain degree of uniqueness in their genetic make-up, while having some affinities with other regional populations in Japan as well as the Nivkhs of the Russian Far East.
Mark J. Hudson of Nishikyushu University posits that Japan was settled by a Proto-Mongoloid population in the Pleistocene who became the Jōmon, and that their features can be seen in the Ainu and Okinawan people. The Jomon share some physical characteristics, such as relatively abundant body hair, with Caucasians, but anthropological genetics shows them to derive from a separate genetic lineage from that of Europeans.
Anthropologist Joseph Powell of the University of New Mexico said that the Ainu descend from the Jōmon people who are an East Asian population with "closest biological affinity with south-east Asians rather than western Eurasian peoples". Turner found remains of Jōmon people of Japan to belong to Sundadont pattern similar with the Southern Mongoloid living populations of Taiwanese aborigines, Filipinos, Indonesians, Thais, Borneans, Laotians, and Malaysians.
Around 400–300 BC, the Yayoi people began to enter the Japanese islands, intermingling with the Jōmon. The Yayoi brought wet-rice farming and advanced bronze and iron technology to Japan. Although the islands were already abundant with resources for hunting and dry-rice farming, Yayoi farmers created more productive wet-rice paddy field systems. This allowed the communities to support larger populations and spread over time, in turn becoming the basis for more advanced institutions and heralding the new civilization of the succeeding Kofun period.
The estimated population in the late Jōmon period was about one hundred thousand, compared to about three million by the Nara period. Taking the growth rates of hunting and agricultural societies into account, it is calculated that about one and half million immigrants moved to Japan in the period.
According to an analysis of the 1000 Genomes Project's sample of Japanese from the Tokyo metropolitan area, the mtDNA haplogroups found among modern Japanese include D (42/118 = 35.6%, including 39/118 = 33.1% D4 and 3/118 = 2.5% D5), B (16/118 = 13.6%, including 11/118 = 9.3% B4 and 5/118 = 4.2% B5), M7 (12/118 = 10.2%), G (12/118 = 10.2%), N9 (10/118 = 8.5%), F (9/118 = 7.6%), A (8/118 = 6.8%), Z (4/118 = 3.4%), M9 (3/118 = 2.5%), and M8 (2/118 = 1.7%).
A 2011 SNP consortium study done by the Chinese Academy of Sciences and Max Planck Society consisting of 1719 DNA samples determined that Koreans and Japanese clustered together confirming the findings of an earlier study that Koreans and Japanese are closely related. However the Japanese were found to be genetically closer to South Asian populations as evident by a genetic position that is significantly closer towards South Asian populations on the principal component analysis (PCA) chart. Some Japanese individuals are also genetically closer to Southeast Asian and Melanesian populations when compared to other East Asians such as Koreans and Han Chinese, indicating possible genetic interactions between Japanese and these populations.
A 2010 large genome-wide association study of East Asian populations by Jungsun Jung et al. found that the Japanese are closer to Han Chinese, but the Koreans are relatively far away from Han Chinese if compared to Japanese.  This study also included Native Americans, Vietnamese, Cambodians, Europeans and Africans. It was also found in the same paper that, going by Identity By State (a more accurate indicator of genetic similarity and distance compared to Fixation Index) results, the Japanese are more related to the Vietnamese when compared to the Mongolians and Koreans. The Koreans and Mongolians were found to be the least genetically related to the Vietnamese. The Japanese were also more similar by IBS to the Mongolians than the Koreans were. However, further studies need to be conducted to infer about relationships between the Jomon Japanese and their genetic relationships to other East Asian ethnic groups to better understand the origins of the Japanese people.
A 2008 study about genome-wide SNPs of East Asians by Chao Tian et al. reported that Japanese, Koreans and Han Chinese are genetically distinguishable from southeast Asians, and that the Japanese are related to Koreans who are related to Han Chinese, however the Japanese are relatively genetically distant from Han Chinese if compared to Koreans. For some principle component analyses, the Japanese are genetically similar to Cambodians, highlighting genetic similarity between these two ethnic groups. 
During the Japanese colonial period of 1895 to 1945, the phrase "Japanese people" was used to refer not only to residents of the Japanese archipelago, but also to people from colonies who held Japanese citizenship, such as Taiwanese people and Korean people. The official term used to refer to ethnic Japanese during this period was "inland people" (内地人,naichijin?). Such linguistic distinctions facilitated forced assimilation of colonized ethnic identities into a single Imperial Japanese identity.
Article 10 of the Constitution of Japan defines the term Japanese based on the Japanese Nationality. Indeed, Japan accepts a steady flow of 15,000 new Japanese citizens by naturalization (帰化) per year. The concept of the ethnic groups by the Japanese statistics is different from the ethnicity census of North American or some Western European statistics. For example, the United Kingdom Census asks ethnic or racial background which composites the population of the United Kingdom, regardless of their nationalities. The Japanese Statistics Bureau, however, does not have this question. Since the Japanese population census asks the people's nationality rather than their ethnic background, naturalized Japanese citizens and Japanese nationals with multi-ethnic background are considered to be ethnically Japanese in the population census of Japan. Professor John Lie, from the University of California, Berkeley, in spite of the widespread belief that Japan is ethnically homogeneous, believes it is more accurate to describe Japan as a multiethnic society. Even though such claims have long been rejected by other sectors of Japanese society such as former Japanese Prime Minister Tarō Asō, who has once described Japan as being a nation of "one race, one civilization, one language and one culture".
As a result, the word kei (系, can be translated roughly as lineage or origin) is used when the Japanese citizen describe their origin of ancestors other than the Japanese archipelago. For example, Tanya Ishii, a former Japanese member to the Japanese Diet referred herself as a "Russian Japanese" (ロシア系日本人,Roshiakeinihonjin?), since she had Russian roots from her maternal lineage.
^Zheng H-X, Yan S, Qin Z-D, Wang Y, Tan J-Z, et al. 2011 Major Population Expansion of East Asians Began before Neolithic Time: Evidence of mtDNA Genomes. PLoS ONE 6(10): e25835. doi:10.1371/journal.pone.0025835