The Kofun period starts right after the Iron Age agricultural society of the Yayoi. From all the warring kingdoms of the Yayoi, a clan emerges victorious. Its name is Yamato, the family which will establish the Japanese imperial line. This is why some historians name this timeline as Yamato. In order to strengthen their rule, Yamato leaders built an official Shinto religion and huge burial mounds for the political elite. Kofun is actually a Japanese terminology for burial mounds. At the end of the Kofun period, massive spiritual and technological imports from China brought a tremendous cultural revolution. Japan slowly began to be one of the most civilized and evolved nations of the world.
Separating Yayoi culture from Kofun culture is not an easy task for historians. Firstly, archaeologists discovered small burial mounds in the Late Yayoi, making the transition difficult to identify. Secondly, technology evolved but the whole period had no technical revolutions. In general, specialists highlight some main characteristics for understanding the changes in the era. Yayoi was a shamanistic, warlike and matriarchal society, while Kofun had an organized religion, was a patriarchal society and warfare was more limited by strong leaders.
Yamato’s accession starts in parallel with the end of civil war in China. The three kingdoms of Wu, Shu and Wei were unified and replaced by the rule of the Jin dynasty. With a population of 35 million people, it became a model for the Yamato court as the Japanese rulers were seeking legitimacy from the Chinese emperors. With the downfall of the Jin emperors, constant civil war between Chinese empires prevented further official communications with Japan. On the other hand, archaeological evidence points to constant trade, most likely undertaken with Korean intermediaries or with Chinese traders on a private level, instead of state-to-state trade.
Since it is linked with the destiny of Yamato rulers, Kofun jidai is separated into three large parts. The first one includes the first 150 years, when the Yamato kingdom slowly expanded its dominance in Japan. The second one is represented by the peak of the Yamato kingdom’s power, characterized by huge burial mounds, big and well-supplied armies, and attempts to expand into Korea. Introduction of Buddhism and other major reforms mark the final stage, when the legitimacy and strength of the Yamato kings faded, as they struggled to remain in power.
It seems that burial mound practice was imported from China and Korea, but the ceremony was widely held at that time mostly in Japan. The earliest ones were built from natural hills. Later burial mounds involved terrible work, as hundreds of workers built these structures using earth, clay, wood and stone from a flatland. In their period of glory, they were concentrated on the eastern shores facing the Sea of Japan, the resting place for Yamato kings. Kofun Daisen located near Osaka was one of the biggest burial mounds. It was 35 meters tall and 480 meters wide. The numerous chambers contained thousand of artifacts and offerings.
Haniwa warriors were statues of soldiers from the Kofun era measuring between 1 and 2 meters long that were placed on top of the tombs. Their purpose is still debated. They could be guarding the burial mounds of the ruling elite from evil spirits or just marking the separation between the realm of the living and the mystical underworld. From an aesthetic point of view, the statues were highly complex, helping historians to reconstruct what Kofun soldiers really looked like.
Combining information from haniwa statues and weapons unearthed from the ground, archaeologists have been able to understand how the Kofun armies fought. Ancient chronicles from China and Korea, alongside Kojiki and Nihon shoki, also helped in completing the big image. The military organization was quite complex, but the real difference was almost certainly made by Yamato’s heavy cavalry.
Art prospered under the guidance of free craftsmen from Korea and China who formed small colonies in Japan. Because of their skills, they were protected by the Yamato kings, and were given a special status. In a sense, they were like the precursors of specialized guilds from the Middle Ages in Europe.
Yamato was the strongest Japanese warrior clan of its time, but it wasn't strong enough to defeat all the competitors at once by military means. Instead, Yamato rulers developed the old system of tribe federation from the Yayoi into a tributary and alliance system. The neighboring kingdoms could pledge allegiance, trade and give specific resources to the Yamato. In return, the Yamato offered military and economic aid, and even appointed their allies to vital administrative positions. These regional leaders had the noble title of ‘uji’ and originated from different clans like Mononobe, Munakata, Otomo, Soga, Nakatomi, Haji, Ki and Kagusa.
A team of archaeologists, historians and folklorists tried to reconstruct the religion from the Kofun era. The main burial mounds from Early Kofun were all built at the foot of the Miwa mountain. Connecting archaeological findings with local myths and legends, scientists now believe that Yamato rule was closely linked to the divination of Shinto gods that had their home on the top of this mountain. It seems that Omiwa shrine, the main temple of the Kofun era, was dedicated to the Miwa kami. Somewhat similar to Medieval Christian kings, Yamato divine kings took the legitimacy of their leadership as an intermediate between the land of the living and the land of the gods.
Nintoku is probably buried in the Middle Kofun tomb of Daisen-ryo, the biggest burial tomb of the Kofun jidai. The monument built in his honor and his long reign make him the greatest king of the Kofun era. It should be noted that the dates of his rule are noted in the Nihon shoki chronicle that tends to put historical events earlier than they really were. It is more plausible that Nintoku hegemony happened at least a century later.
Yamato kings initiated several diplomatic missions in Korea. Their most important trade partner became the Korean Kingdom of Paekche, a realm that would become their closest ally in the next era, the Asuka jidai. Inspired by the legendary invasion of the empress Jingu in Korea and backed up by some archaeological evidence, Japanese historians believe that the kingdom of Yamato conquered the southern part of Korea. Korean historians claim that the area was actually a commercial center where the Yamato people were allowed to trade in exchange for paying tribute. Regardless of the truth, the Japanese were expelled or repelled from there by the Korean Kingdom of Silla in 562 AD.
Chinese chronicles note that at least five Yamato rulers sent nine emissaries in order to gain the favor of Chinese emperors and support for establishing a Yamato foothold in Korea. Historians can’t estimate with accuracy if the Japanese adventure into Korea was profitable or just an expensive and exhausting experience that contributed to the gradual downfall of the Yamato divine rulers.
The Kofun political and religious system started to crumble. Keeping in balance so many uji clans was a game that exhausted all the resources of the king. The internal strife overturned all the expansionists plans into Korea and affected the military and economic development of the country. Even in warfare technology and ship building, Yamato was lagging behind Silla. Keitai and Kimmei were the greatest Yamato kings from the Late Kofun era, but they could not prevent the downfall of their house. A radical package of reforms was needed. Unfortunately for the Yamato leaders, Kimmei implemented reforms that, while leading to unprecedented prosperity, ended up destroying their authority.
Emperor Kinmei is the first Japanese historical figure whose existence has been proven by indubitable historical evidence. King Song Myong of Paekche sent a special mission to the Yamato court. The delegation from the Korean kingdom of Baekje arrived in Japan in 538 AD, with the goal of convincing the Yamato kings of the benefits of Buddhism. The context is not clear, but Yamato kings accepted the services of Buddhist monks. This symbolic act marks the arbitrary separation of Kofun jidai from Asuka jidai. The measure triggers a competition between the supporters of Shintoism led by the Mononobe clan, and those who wanted the recognition of Buddhism, gathered around the Soga clan.
At the end of the Kofun era, Yamato’s rule in Japan was fully established in practice and theory. By practice we mean the actual military and economic power, and by theory we refer to political and religious institutions. Shinto shrines spread over all the country, and the Yamato kingdom turned into an empire. Yamato leaders become the first emperors of Japan whose existence is evidenced by certain historical documents. Foreign cultural imports like a writing system, Buddhist and Confucianist ethics have led historians to compare this tremendous spiritual evolution to the one found in Europe in the time of the glorious Hellenic and Roman civilization.
Yamada Shunsuke made a synthesis about the latest discoveries related to the Kofun jidai and the most important contributions of specialists in relation to this subject. This type of research is exploratory, and until things become clearer, it should be treated as fascinating dialectical hypothesis and not as indubitable historical truth. Nevertheless, exploration is the very core of science, and the general presentation could be useful because it puts things already known into an increasingly complicated context. In this way, we are getting closer to the empirical and spiritual reality of the Kofun jidai.
The Horse Riders Invasion Theory was first proposed by Egami Namio and Oka Masao. It is an intriguing concept, but most specialists consider it to be too speculative. In short, it posits that the Yamato kingdom was established by a strong nomadic people from eastern Manchuria who passed through Korea and then conquered the Yayoi people of Japan, using superior military force. More than fifty years have passed since Egami Namio presented his theory and now archaeologists have discovered empirical proofs which bring back the dialectical debate about the origins of the Japanese people. Anyway, Egami Namio was personally decorated for his services by the emperor Akihito.
Theories regarding dual kingship in the Kofun era have been around in the academic sphere for a long time now. In 2013, Naofumi Kishimoto managed to go beyond traditional views. He proposed a new concept of dual kingship of two rulers who shared authority, but were also in competition. Even more captivating is the fact that Kishimoto brings the idea that both leaders were male and that the one charged with the religious sphere was roughly equal to the one with secular concerns. This internal balance of political power was very fragile and unstable. Finally, only in Late Kofun was this system replaced with a more reliable and centralized reign of a single king.
Like Egami Namio, Gina L. Barnes also argues that Early Kofun was radically different from Middle and Late Kofun. Conflicting with a materialist deterministic view, Barnes does not support the idea of a foreign invasion that founded the Yamato kingdom. Her alternative hypothesis is based on the power of ideology. The Yamato kingdom didn’t have the military power to subdue Japan. In reality, Yamato rulers slowly expanded by the force of religious authority represented by the cult for a Queen goddess, an idea originating from China. Himiko was the first reincarnation of that political system.
In the latest archaeological reports from 2013-2014, Tanaka Yutaka and Nakakubo Tatsuo write about the progress of Kofun jidai research and what they think the future will hold. The first researcher is more pessimistic, while the latter has a positive vision about the next years. Nakakubo Tatsuo estimates that Japan holds at least 160,000 burial tombs and that the scientists have made an impressive collection of information about the period. On the other hand, Tanaka Yutaka points out the fact that interest in ancient Japanese history has decreased. His argument is sustained by the decrease in the number of books sold about the subject and by the smaller number of young archaeologists.