Toraijin

Toraijin (渡来人, とらいじん) refers to the Korean emigrants who came to Japan from mainland Asia in ancient times, as well as their descendants. They arrived in Japan as early as the Jōmon or Yayoi period, and their arrival became more significant from the end of the 4th century to the late 7th century. During this period, they introduced Confucianism, learning, medicine, the calendar, and cultural practices such as Sue ware production and weaving to Japan. They were favored by the Yamato Imperial Court, and many were appointed to government positions.

Recent studies of ancient Japanese genomes corroborate the historical records and archaeological data point to arrival of Toraijin and the appearance of new socio-cultural and political changes. A 2021 study published in the journal Science Advances found that the people of Japan bore genetic signatures from three ancient populations rather than just two as previously thought. The study states that in addition to the previously discovered Jōmon and Yayoi strands, a new strand of "majority East Asian ancestry" was hypothesized to have been introduced, most likely from the southern Korean peninsula, during the Yayoi-Kofun transition period that had strong cultural and political affinity with Korea and China.

Impact of Toraijin on Japan
Historical records and archaeological data provide strong support for continued population movements from the continent to the Japanese archipelago via the southern Korean peninsula from 800 BCE to 600 AD. The Toraijin arrived in the archipelago in multiples waves. In the initial wave starting approximately three thousand years ago, the Toraijin introduced wet-rice farming to the archipelago, where the indigenous Jōmon people were engaged in subsistence based primarily on fishing, hunting, and gathering. During the Middle Yayoi period from approximately 350 BCE to 50 CE, Toraijin arrived with bronze technology. During the formative 5th and 6th centuries, they brought horse breeding and horse driven transportation, stoneware pottery, high temperature iron-working, advanced iron tool manufacturing, and their Chinese-based writing system. In addition to technological and cultural contributions, Toraijin also brought the ideologies of Confucianism and Buddhism from the mainland, which were critical to the state formation and socio-cultural changes during the Kofun period and Asuka period. According to Japanese researchers, in each major epoch in Japanese history, Toraijin arriving from the Korean peninsula acted as transmitters and transplanters of advanced continental technology and culture to the Japanese archipelago, just as the population groups on the Korean peninsula experienced similar transformations with the arrival of millet and rice agriculture, bronze and iron objects and technologies, and culture and religion from further west and north in the continent.

History
The period of arrival of the Toraijin can be divided into four categories: 2nd to 3rd century BC, around the 5th century BC The period when the Five kings of Wa ruled, late 5th – 6th century, and seventh century.

The first Torajin, who arrived in the 1st millennium BC, are thought to have introduced rice cultivation and earthenware to Japan (mainly in Kyushu). According to the Chronicles of Japan and the Kojiki, the first major arrival to Japan was during the reign of Emperor Ōjin, but there was a major upheaval on the Korean peninsula at that time. Some people came to Japan to escape the upheaval and introduced iron tools, irrigation technology, and so on. The tools and technology they brought with them may have revolutionized the production methods and labor patterns that had existed until then. They also brought horses and harnesses, and riding came to be practiced.

Kofun and Asuka periods
During the Kofun period and the turbulent Three Kingdoms period of Korea, there was extensive migrations from Korean polities to the Japanese archipelago, particularly from Baekje and Gaya confederacy, both of which developed friendship as well as economic and military alliances with Yamato Kingship. The Wa elites, such as Yamato elites in Kinki, Tsukushi elites in Fukuoka and Kibi elites in Okayama, sought to establish socio-political advantages in the archipelago and welcomed and integrated the newcomers with peninsular goods and advanced technology.

These immigrants settled and re-established themselves as farmers, iron technicians, horse breeders, merchants and traders, dam builders, craftsmen, among others, earning them the name Imaki no Tehito (今來才技, “recently arrived skilled artisans”) in the Nihon Shoki. Groups arriving from the peninsula have settled in and formed communities in various parts of the archipelago, including Fukuoka in northern Kyushu to Okayama on the Inland Sea, to the Kyoto–Osaka– Nara area, to Gunma north of Tokyo, and as far as Sendai in northeastern Honshu.

In 552 AD, King Seong of Baekje sent envoys to the Yamato court, bringing Buddha statues and Buddhist classics, and Buddhist culture was also introduced to Japan. After Buddhism was introduced to Japan, it became one of the main religions in Japan and a part of today's Japanese culture.

While migrants initially settled in Kyushu due to geographic proximity to the peninsula, by the fourth century, migrants had shifted their destination to the Kinki region, the core base of the Yamato elites, of Nara, Osaka, Kyoto, and Otsu region.

After entering the Asuka period, many Japanese royals and ministers believed in Buddhism, such as Prince Shōtoku and Soga Mako, and devoted themselves to promoting Buddhism. The reason why Baekje people went to Japan was that Japan asked Baekje for craftsmen and Doctor of the five classics and escaped from Goguryeo.

The Yamato basin was the home of powerful clans with Toraijin roots, such as the Soga clan with Baekje origins and which emerged as the most powerful clan in the Yamato by the middle of 6th century, and the Yamatonoaya clan with roots in the Gaya confederacy and Baekje. Notably, early in the eighth century, Lady Takano Niigasa, a member of the Yamatonoaya clan, married the Yamato Prince Shirakabe (the future King Kōnin) and gave birth to Yamanobe in 737 in Nara, who was enthroned in 781 as Emperor Kanmu.

Other notable Toraijin clans with imperial ties included Kudara no Konikishi clan and Yamato no Fuhito clan, both of Baekje descent. Other representative Toraijin groups of the 4th and 5th centuries were the Hata clan and the Kawachinofumi clan. These Toraijins possessed superior technology and ability, and were fundamental to Japan's nation-building. The Hata clan is descended from Yuzuki no Kimi, who came from Silla on the Korean Peninsula around the 4th or 5th century (Hadan may be their place of origin). Yuzuki no Kimi came to Kyushu with 30,000 to 40,000 laborers from 127 prefectures. They served the Yamato royal court as officials in charge of finances. His headquarters was originally located in Yamaboshi, Kyoto, but he later moved to Uzumasa (Kyoto City). Along with their activities in the center of Japan, the descendants of the Hata extended their influence nationwide, from Owari and Mino to Bicchu and Chiku.

In the 7th century, exiles from Baekje, which had been defeated at the Battle of Baekgang, entered Japan. The technology and culture brought by the Toraijin contributed to the advanced development of Japan at that time. Toraijin occupied an important position in the military and political affairs of the Yamato regime due to their advanced skills in arms manufacturing, weaving, and agriculture. They also made significant contributions to the development of Japanese culture.

Toraijin Population Estimates
Based on estimates from studies of Senzuka (cemeteries of “thousand tombs”) belonging to the Toraijin from the southwestern Korean peninsula and their descendants, Shinichirō Ishiwatari postulated that at least a million people from the peninsula arrived in the archipelago just during the 125 years between 475–600 CE.

According to the book Shinsen Shōjiroku compiled in 815 CE, a total of 326 out of 1,182 families in the Kinai area on Honshū were regarded as people with foreign genealogy. The book specifically mentions that 163 were from unknown origins, 104 such families were from Baekje, 41 were from Goguryeo, 9 were from Silla, and 9 were from Gaya. These families are not inherently considered noble, but rather notable.

According to the 2021 Japanese genome study, the genetic profile of present-day Japanese population was established by the three major ancestral components in place by the Kofun period, with the East Asian ancestry component introduced during the Kofun period accounting for nearly 70% of the admixture proportion, while Yayoi component accounting for 15-20% and the remainder by the Jōmon component.