The Yamato period (better known as the Kofun period) is the period of Japanese history when the Japanese Imperial court ruled from modern day Nara prefecture, then known as Yamato province.
While conventionally assigned to the period circa 250 - 710 CE, the actual start of Yamato rule is disputed. The court's supremacy was challenged throughout the period from Bizen and Bitchu provinces in what is now known as Okayama prefecture, and it was only into the 6th century CE that the Yamato clans could be said to have any major advantage over their neighbouring clans.
Hence, Japanese archaeologists (and textbooks) tend to prefer the less deterministic term Kofun period, which reflects the diagnostic archaeological feature, the large, often keyhole shaped burial mounds (kofun) found across mainland Japan.
The Yamato Period can be divided into two parts based upon the arrival of Buddhism:
The story circulates inside South Korea that until Korea introduced the concept of civilization, the Japanese archipelago was inhabited by the hunter-gatherer Jomon people consisting of Ainu and Malayo-Polynesian people. The Kaya (Karak) kingdom that based around Pusan introduced the rice-cultivation and conquered Ainu and Malayo-Polynesian aborigines. This theory is based around the theory by Egami Namio that the powerful horse riding race from north brought about the dramatic change from Jomon to Yayoi culture.
Based on only fact that Emperor Kammu's mother was a Baekje descendant, the unified nation-state on the Japanese islands was claimed to have been established at the end of the fourth century by the Paekche people from the Korean peninsula. Based on the similarity from using Chinese character as a writing methods for centuries, the modern Korean is claimed to be the father of the modern Japanese. The example claimed by South Korean is that the city of Nara got its name from the modern Korean word for "nation" (Nara).
On 1974, Ishida Eiichiro, a Tokyo University professor of cultural anthropology, once stated: "Detailed research by historians had made clear that the greatest wave of immigration took place immediately after the unification of Japan by the Yamato court. If the Yamato court was established without any relation to Korea, how can these facts be explained?"
Through the method of Radiocarbon dating, carefully comparing Japanese classical texts against Chinese classical texts, gathering what little information on the actual language spoken by Baekje people, the theory that Korea introduced civilization to Japan had become outdated ignored even by South Korean historians. Much like the claim that people from the legendary Atlantis taught the Roman Empire secrets of building an empire, it persists as a cult belief in South Korea.
The cultivation of rice that had been marked as a single most important introduction from Korea has since been mostly denied by comparing DNA of rice from China, Japan, Korea, Okinawa, Vietnam, and other South East Asian countries. The DNA of rice from Korea was similar to Japan but it was significantly different then that of China or Okinawa. It was even more different than that of other Asian countries. The DNA of rice from Japan was similar to that of China and Okinawa while retaining similarities with that of Korea. This means that rice had come from China by the way of Okinawa and moved up north through Japan into Korea.
The previously believed normadic lifestyle of Jomon had since been denied as well. Instead of an external influence forcing Jomon people into settlements and agricultural lifestyle, Jomon people already started farming to support themselves and relied on trade for gathering necessities. Chestnut trees and acorn trees were widely planted and these became staple foods. Both trees grew easily and they can be cut down to make large buildings. The rice farming introduced in the late Jomon period also did not have an influence as previously believed. Less than a third of the crops are believed to be rice and crops like millet, Japanese millet, and wheat.
The theory that an ancient Japanese word Nara comes from the modern Korean word Nara lit. country, is a merely chance resemblance from comparing thousands of words trying to find a similarity. The Japanese word Nara has never had the meaning of country, it comes from the word Nada or Nadaraka meaning a flat place. Indeed, Nara is a small flat plane in the mountainous region of Nara prefecture.
There is no reliable information on Korea written by Korean themselves of these periods. The earliest Korean writing of any kind does not exist until 12th century and it is still unknown today what languages extinct Korean kingdoms spoke. Both China and Japan consistently wrote accounts of history but these were mostly written in Chinese characters in Chinese and offer little clue to languages in Korea. Since Nara period, Japan started to write using both Chinese and a Chinese style Japanese, but Korean kingdoms did not use Chinese characters to write in Korean until 16th century. Kojiki and Nihongi gives the most detailed accounts, but both also states that the Yamato kingdom had always influenced events in Korea by sending in troops, sometimes as much as 100,000, and maintained an outpost in Korea. In them it is also stated that the clan from where the mother of Kammu came, was given the status of a retainer under the emperor after the Baekje kingdom fell. These accounts are simply ignored or claimed as a propaganda by Japan and China trying to lie about the dominance by Korea in East Asia.