Their most widely known ethnonym is derived from the word ainu, which means "human" (particularly as opposed to kamui, divine beings) in the Hokkaidō dialects of the Ainu language; Emishi, Ezo or Yezo (蝦夷) are Japanese terms, which are believed to derive from the ancestral form of the modern Sakhalin Ainu word enciw or enju, also meaning "human". The term (meaning "comrade" in Ainu) is now preferred by some members of this minority. Note that Yezo was also an earlier name of the island of Hokkaidō, if not of the homonymous prefecture.
Ainu culture dates from around 1200 CE and recent research suggests that it originated in a merger of the Okhotsk and Satsumon cultures. Their economy was based on farming as well as hunting, fishing and gathering.
Full-blooded Ainu are mostly fair-skinned, with the men generally having dense hair development. Many early investigators proposed a Caucasian ancestry although recent DNA tests have found no traces of Caucasian ancestry. Genetic testing of the Ainu people has shown them to belong mainly to Y-haplogroup D. The only places outside of Japan in which Y-haplogroup D is common are Tibet and the Andaman Islands in the Indian Ocean. In a study by Tajima et al. (2004), two out of a sample of sixteen (or 12.5%) Ainu men were found to belong to Haplogroup C3, which is the most common Y-chromosome haplogroup among the indigenous populations of the Russian Far East and Mongolia; Hammer et al. (2006) tested another sample of four Ainu men and found that one of them belonged to haplogroup C3. Some researchers have speculated that this minority of Haplogroup C3 carriers among the Ainu may reflect a certain degree of unidirectional genetic influence from the Nivkhs, a traditionally nomadic people of northern Sakhalin Island and the adjacent mainland, with whom the Ainu have long-standing cultural interactions. According to Tanaka et al. (2004), their mtDNA lineages mainly consist of haplogroup Y (21.6%) and haplogroup M7a (15.7%). Mitochondrial DNA haplogroup Y is otherwise found mainly among Nivkhs, as well as at lower frequency among Koreans, Mongols, Tungusic peoples, Koryaks, Itelmens, and Austronesians; haplogroup M7a, on the other hand, is found elsewhere almost exclusively among Japanese, Ryukyuans, and Koreans. A recent reevaluation of cranial traits suggests that the Ainu resemble the Okhotsk more than they do the Jōmon. This agrees with the reference to the Ainu culture being a merger of Okhotsk and Satsumon cultures referenced above.
Some have speculated that the Ainu may be descendants of a prehistoric group of humans that also produced indigenous Australian peoples. In Steve Olson's book Mapping Human History, page 133, he describes the discovery of fossils dating back 10,000 years, representing the remains of the Jōmon, a group whose facial features more closely resemble those of the indigenous peoples of New Guinea and Australia. After a new wave of immigration, probably from the Korean Peninsula, some 2,300 years ago, of the Yayoi people, the Jōmon were pushed into northern Japan. Genetic data suggest that modern Japanese are descended from both the Yayoi and the Jōmon.
Groundbreaking genetic mapping studies by Cavalli-Sforza have shown a sharp gradient in gene frequencies centered in the area around the East Sea/(Sea of Japan), and particularly in the Japanese Archipelago, that distinguishes these populations from others in the rest of eastern Asia and most of the American continent. This gradient appears as the third most important genetic movement (in other words, the third principal component of genetic variation) in Eurasia (after the "Great expansion" from the African continent, which has a cline centered in Arabia and adjacent parts of the Middle East, and a second cline that distinguishes the northern regions of Eurasia and particularly Siberia from regions to the south), which would make it consistent with the early Jōmon period, or possibly even the pre-Jōmon period.
In 1899 the Japanese government passed an act labeling the Ainu as former Aborigines, with the idea they would assimilate. The act was replaced in 1997—until then the government had stated there were no ethnic minority groups. It was not until June 6, 2008 that Japan would formally recognise the Ainu as an indigenous group. As Japanese citizens, the Ainu are now governed by Japanese laws and judged by Japanese tribunals, but in the past, their affairs were administered by hereditary chiefs, three in each village, and for administrative purposes the country was divided into three districts, Saru, Usu and Ishikari, which were under the ultimate control of Saru, though the relations between their respective inhabitants were not close and intermarriages were avoided. The functions of judge were not entrusted to these chiefs; an indefinite number of a community's members sat in judgment upon its criminals. Capital punishment did not exist, nor did the community resort to imprisonment. Beating was considered a sufficient and final penalty. However, in the case of murder, the nose and ears of the culprit were cut off or the tendons of his feet severed. Intermarriages between Japanese and Ainu were actively promoted by the Ainu to lessen the chances of discrimination against their offspring. As a result, many Ainu are indistinguishable from their Japanese neighbors. There are many small towns in the southeastern or Hidaka region where full-blooded Ainu may still be seen such as in Nibutani. In Sambutsu especially, on the eastern coast, many children of such marriages may be seen.
The 400,000 Japanese citizen inhabitants of Sakhalin (including all indigenous Ainu) were deported following the conquest of the southern portion of the island by the Soviet Union in 1945 at the end of World War II.
Today, many Ainu dislike the term Ainu because once it had been used with derogatory nuance and prefer to identify themselves as Utari (comrade in the Ainu language). In official documents both names are used.
According to the Russian Empire Census of 1897, 1446 persons in the Russian Empire reported Ainu language as their mother tongue, 1434 of them in Sakhalin Island. For historical reasons nearly all Ainu live in Japan now. The southern half of Sakhalin was acquired by Japan as a result of the Russo-Japanese War of 1904-05, but at the end of World War II in 1945, the Soviets declared war on Japan and took possession of the Kurile islands and southern Sakhalin. The Ainu population, as previously Japanese subjects, were "repatriated" to Japan.
There are, however, a small number of Ainu living on Sakhalin, most of them descendants of Sakhalin Ainu who were evicted and later returned. There is also an Ainu minority living at the southernmost area of the Kamchatka Peninsula and on the Kurile Islands. However, the only Ainu speakers remaining (besides perhaps a few partial speakers) live solely in Japan. There, they are concentrated primarily on the southern and eastern coasts of the island of Hokkaidō.
Due to intermarriage with the Japanese and ongoing absorption into the predominant culture, there are no truly Ainu settlements existing today. The town of Nibutani in Hidaka area (Hokkaido prefecture) has a number of Ainu households and a visit to some of the Ainu owned craft shops close to the Ainu museums (there are two of them in Nibutani) is an opportunity to interact with the Ainu people. Many "authentic Ainu villages" advertised in Hokkaido such as Akan and Shiraoi are tourist attractions and provide an opportunity to see and meet Ainu people.
Traditional Ainu culture was quite different from Japanese culture. Never shaving after a certain age, the men had full beards and moustaches. Men and women alike cut their hair level with the shoulders at the sides of the head, trimmed semicircularly behind. The women tattooed their mouths, and sometimes the forearms. The mouth tattoos were started at a young age with a small spot on the upper lip, gradually increasing with size. The soot deposited on a pot hung over a fire of birch bark was used for color. Their traditional dress was a robe spun from the inner bark of the elm tree, called attusi or attush. Various styles of clothing were made, and consisted generally of a simple short robe with straight sleeves, which was folded around the body, and tied with a band about the waist. The sleeves ended at the wrist or forearm and the length generally was to the calves. Women also wore an undergarment of Japanese cloth. Modern craftswomen weave and embroider traditional garments which command very high prices. In winter the skins of animals were worn, with leggings of deerskin and in Sakhalin, boots were made from the skin of dogs or salmon. Both sexes are fond of earrings, which are said to have been made of grapevine in former times, as also are bead necklaces called tamasay, which the women prized highly. Their traditional cuisine consists of the flesh of bear, fox, wolf, badger, ox or horse, as well as fish, fowl, millet, vegetables, herbs, and roots. They never ate raw fish or flesh; it was always boiled or roasted. Their traditional habitations were reed-thatched huts, the largest 20 ft. (6 m) square, without partitions and having a fireplace in the center. There was no chimney, only a hole at the angle of the roof; there was one window on the eastern side and there were two doors. The house of the village head was used as a public meeting place when one was needed. Instead of using furniture, they sat on the floor, which was covered with two layers of mats, one of rush, the other of flag; and for beds they spread planks, hanging mats around them on poles, and employing skins for coverlets. The men used chopsticks when eating; the women had wooden spoons. Ainu cuisine is not commonly eaten outside Ainu communities; there are only a few Ainu-run restaurants in Japan, all located in Tokyo or Hokkaidō, serving primarily Japanese fare.
Some Ainu in the north are members of the Russian Orthodox Church.
In March 1997, the Ainu were recognized by a Japanese court as an indigenous and minority people. Ainu issues did not matter in the sphere of public policy until then. There was a limited outcry when the Saru River was dammed and the upriver town of Nibutani, one of the largest traditional Ainu villages, was flooded and the land expropriated from its Ainu owners. The reservoir was designed to service an industrial development project on the coast of Hokkaido, and despite the industrial project's cancellation, the government persisted in building the dam. Two Ainu residents, Kaizawa Tadashi and Kayano Shigeru, refused to sell their land, and in 1993 filed lawsuit against the expropriation. The expropriation was upheld, and for the first time, a Japanese Court recognised that the Ainu's indigenous rights had been violated.
As signatories of the United Nations Treaty, the International Covenant on Civil and Political Rights (ICCPR) which was signed by Japan in 1979, the Japanese had been forced to face the issue that the Ainu were indeed indigenous and minority peoples, which supported the Ainu in their pursuit of their rights to their distinct culture and language. There are many different organizations of Ainu trying to further their cause in many different ways. There is an umbrella group of which most Hokkaido Ainu and some other Ainu are members, called the Hokkaido Utari Association, originally controlled by the government with the intention of speeding Ainu assimilation and integration into the Japanese nation-state, which now operates mostly independently of the government and is run exclusively by Ainu.