Ancient Relations between Japan and Korea: from prehistory through the Eighth Century
The tragic late-nineteenth and early-twentieth centuries has obscured one of the most last influences in the history of two great nations of East Asia : Japan and Korea. The relationship between Japan and Korea had been dramatically different in the centuries before 1870, with the exception of Hidyoshi’s invasions in the 1590s. Tokugawa Japan maintained a cordial relationship with Joseon Korea. The links between Korea and Japan become stronger the more one goes back into history. For, in the ancient period, Koreans and Japanese were allies. Specifically, the Korean Kingdom of Baekje was the closest ally of the ancient Yamato State in Japan. So much of early Japanese culture came, not from China, but from the Korea peninsula. It was from Korea that Buddhism spread to Japan. Indeed, Japan’s oldest surviving temples — most notably Horyu-ji — were almost certainly built by Korean laborers and show clear influences of architectural styles from Baekje. The Japanese and Baekje royal families intermarried. The rich and endlessly fascinating civilizations of Japan and Korea are like two offshoots from a single tree trunk.
No surviving maps exist for East Asia, from the perspectives of either Japan or Korea before the beginning of the fifteenth century. Therefore we will have to use the Kangnido Map of 1402 to gain some insights into how earlier Japanese and Koreans may have viewed the region. We can immediately see the centrality of China. We can also see that the shape of Korea is far more accurate in this map than that of Japan. Africa and the Arabian Peninsula (on the far left) are not nearly as accurate, though were at least known to fifteenth-century Koreans. We can assume that the Korean and Japanese views of East Asia from a thousand years earlier were far more limited and centered entirely on East Asia, with a vague understanding of places farther away like India.
To reconstruct a picture of what Japanese-Korean relations were like in the period from prehistory through the eighth century, I will be using the following sources: histories which cover the period (like the Nihongi and Samguk sagi), archaeological evidence, and surviving artistic and archaeological similarities between items and buildings found in Japan and Korea. Korean influence on the Japanese archipelago goes back before recorded history. This article will stop in the eighth century with the Japanese Emperor Kanmu. In 2001, then reigning Emperor Akihito made a statement about the Korean portion of his own ancestry — a subject of much controversy in Japan.
“I feel a connection to Korea through annotations made in the `Continued Record of Japan`, which stated that the mother of Emperor Kanmu was a descendant of Baekjae`s King Muryong.”
The controversial nature of the ethnic identity of Japan’s Imperial Family is largely a product of modern (post-1868) politics. Indeed, studying the subject is been somewhat difficult because the Japanese Imperial Household Agency has stood in the way of excavating imperial tombs from the Meiji period (1868–1912) until 2018, when it began to allow excavations. Such excavations will be essential in understanding prehistoric Japan. Most of the large, keyhole-shaped tombs in the country were constructed before writing became widespread.
The people now known as Japanese are descended from a people called the Yayoi (also a period name, from c.300 BCE — c.300 CE). The original inhabitants of the northern portion of Japanese archipelago were the Ainu, a Caucasian people who had migrated south from Siberia. Gradually, they were pushed north with an influx of immigrants from the Korean Peninsula. These immigrants brought with them wet rice agriculture and techniques in metallurgy. Chinese influences were also present, but far more common were influences from Korea.
The earliest writings of any kind in Japan come from the 400s, with many of these being inscriptions. Japanese books were not published for another couple centuries and most of these early books are not extant. The earliest surviving historical (really mythological-historical) accounts from Japan are the Kojiki(712, ‘Record of Ancient Matters) and the Nihongi (720 Chronicles of Japan from Earliest times to 697). Both of these works are products of politics originating in the previous decades when the Yamato State, under Emperor Temmu and Empress Jito, was expanding its power. This nascent Japanese state did not control all of Japan or even all of the main island of Honshu. Instead it was built up of extended clans, growing in power and influence. Predecessors of these two mytho-historical accounts were created by order of the court in order to legitimize the power of the Yamato Clan over other clans. The Kojiki and Nihongi were ultimately the new and improved versions created just after the first permanent Japanese capital was established at Heijokyo (Nara) in 710.
The Kojiki and Nihongi both recount the lives and deeds of legendary emperors going back to Jimmu in 660 BCE. The earliest reigning emperor for which there is historical evidence is Kimmei (r.539-571). Kimmei’s immediate predecessors probably did exist however, the further back one goes, the less clear things become. Therefore, it is necessary to analyze these valuable, but problematic records, critically. The Nihongi is more helpful in painting a picture of ancient Japan as the Kojiki is far more concerned with Shinto mythology as it relates to the origins of the Japanese Imperial Family. The Nihongi mentions the Korean Kingdom of Baekje and asserts that there was a Yamato outpost on the Korean peninsula, though this latter claim is contested. In the modern period, Japanese nationalists asserted that this was a colony, though this was not likely to be the case. There could have been a diplomatic or trading post but probably not more than that. Japan did not send a military force to the Korean Peninsula until 663, and even then it was to help the Kingdom of Baekje against the Tang-Silla coalition.
In the sixth century, Buddhism was brought to Japan by emissaries from the Kingdom of Baekje. The textbook date for this is 538, when delegate sent by the King of Baekje presented the Japanese court with a Buddha statue. The integration of Buddhism into Japanese culture was far from smooth — supporters and opponents of Buddhism struggled for control at court throughout the sixth century before an amalgamation of Buddhism and Shinto began to take place. Japan’s early Buddhist temples were built with the aid of Korean labor and Korean architectural ideas imported from Baekje. This includes the buildings for Horyu-ji, a UNESCO World Heritage Site and home to the oldest freestanding wooden structures on the planet.
The oldest surviving chronicle of Korean history is called the Samguk sagi, and this text dates to 1145. Though it is much later than the Japanese records, it is still a valuable resource for understanding the Korean perspective of Japanese-Korean relations during the Three Kingdoms Period (Goguryeo, Silla, Baekje) of Korean history. Historian Gim Busik (1075–1151) compiled the Samguk sagi after analyzing a variety of historical records which existed in his own time to create a history of Korea. Recently, the Korean government recognized the Samguk sagi as a National Treasure of South Korea. In the Samguk sagi, Japan appears to be more of a peripheral state in association with Baekje. The linked account, from the 2018 Journal of Korean Studies, discounts the notion that Japan could have had anything like a colony on the Korean peninsula in ancient times. This is, in my view, quite correct. Even accounts of Japanese-Korean relations recorded in the Nihongi are likely to make Japan seem more of a dominant power than it was. Japan was the nation lucky enough to be outside the Korean peninsula when the Tang-Silla alliance defeated and conquered Baekje in 660. The Japanese had come to the aid of Baekje and were defeated in a massive naval battle. It seems quite likely that, before this battle, it was the Kingdom of Baekje that was the superior (in terms of cultural sophistication and technological innovation) nation. The Samguk sagi, however, has its shortcomings. It was written long after the events it recounts and probably makes Japan more peripheral than it really was for Baekje. After all, Baekje and Japanese royal families intermarried and Baekje refugees (including princes) fled to Japan after the defeat inflicted by the Tang-Silla alliance in 660.
Relations between Japan and Korea continued on and off over the course of the following centuries. During the Tokugawa period (1603–1868), formal diplomatic relations were maintained between the Korean Kingdom of Joseon and Japan as an important exception to the Japanese isolation policy. It was the Tokugawa Government that established a relation with Korea that would likely serve as a better example for diplomats to look back upon than practically anything that occurred between Japan and Korea during the dark decades between 1870 and about 1970.