Kofun Period
From Keyhole Tombs to Imperial Thrones: The Kofun Period’s Monumental Leap
From Keyhole Tombs to Imperial Thrones: The Kofun Period’s Monumental Leap
Our journey through early Japanese history has already taken us from the cord‑marked pots of the Jōmon period to the rice paddies of the Yayoi era. We watched hunter‑gatherers settle down, saw wet‑rice cultivation take over the archipelago and learned how bronze and iron tools changed everything. But history never stands still. Like a sequel that outshines the original, the Kofun period (c. 250–538 CE) takes the innovations of the Yayoi and scales them up – literally. Where the Yayoi dabbled in irrigation ditches and bronze bells, the Kofun people dug moats around tombs the size of small hills. Where earlier villagers built pit houses and raised granaries, Kofun elites erected keyhole‑shaped mounds hundreds of metres long and filled them with treasures fit for a ruler. In this post we continue our story, tying the Kofun period to the foundations laid in the Yayoi era. We’ll explore the monumental tombs that give the period its name, meet the enigmatic haniwa clay figures who guarded those tombs, and follow the rise of the Yamato clan from a regional power to the nucleus of an imperial state. Along the way we’ll sprinkle in humour – because what’s a massive burial mound without a little levity? – and plenty of educational insight. By the end you’ll see how the Kofun period bridges prehistoric innovation and the dawn of recorded Japanese history.
To understand the Kofun period, we must start with the legacy of the Yayoi. The Yayoi brought wet‑rice agriculture, metallurgy and social stratification to Japan, transforming small bands of hunter‑gatherers into settled farming communities. This agricultural surplus allowed some families to accumulate wealth and power. Over time, those elites began to differentiate themselves not only in life but in death. During the late Yayoi, some graves already contained bronze mirrors and beads, hinting at emerging status differences. It wasn’t long before burial practices took a colossal leap. The word kofun literally means “ancient tomb.” The practice of constructing sepulchral mounds was introduced from the Asian continent around the third century CE and quickly became a hallmark of social prestige[1]. Early tombs were relatively modest – a coffin buried at the top of a natural hill or inside a simple stone chamber. But by the late fourth and fifth centuries, burial mounds grew to monumental proportions. They varied in shape – round, square or the distinctive keyhole shape, which combines a square platform with a circular rear. Some stretched several hundred metres and were surrounded by moats; others stood atop natural ridges and boasted multiple tiers. Grave goods also escalated: elite burials contained bronze mirrors, iron weapons, horse trappings, jewelry and clay vessels, reflecting both wealth and an ideology that equated size with divine authority[1]. If the Yayoi period was about planting seeds (literally and figuratively), the Kofun era was about harvesting prestige. Agricultural surplus funded the labour necessary to build these mounds. The same irrigation systems that made rice paddies possible were expanded to flood moats around tombs. Iron tools perfected during the Yayoi were put to work cutting soil and shaping earthen ramps. Without the agricultural and technological groundwork laid by their ancestors, the Kofun builders would have had nothing to build with or for.
What did these monumental tombs look like? Imagine a small island surrounded by water, accessible only by a single causeway. The largest kofun, the Daisenryō Kofun (also known as Emperor Nintoku’s tomb) in modern Osaka, measures about 486 metres long and is encircled by three moats[2]. Constructing such a mound required thousands of labourers and an impressive command of engineering. Scholars believe that the shape and scale of a kofun broadcasted its occupant’s power far and wide. A round mound may signal a local chieftain, while a colossal keyhole could proclaim the arrival of a regional king. The moats not only served as defensive barriers but also symbolised the boundary between the realm of the living and that of the dead. Not all kofun were so grand. Many mounds were smaller, roughly 15 metres across, and clustered into cemeteries for lower‑ranking elites[1]. As the period progressed, tomb sizes and decorations became more widely used across the social spectrum. In the early centuries, burial goods were minimal; by the sixth century, the chambers contained painted murals and lavish grave goods. In some cases, natural hills were reshaped to create tombs; in others, earthen mounds were built from scratch on flat ground. Regional variations also emerged, with differences in mound size, layout and the arrangement of surrounding haniwa figures, reflecting local styles and social networks.
One of the most enchanting aspects of the Kofun period is the appearance of haniwa (埴輪), hollow terracotta cylinders and sculptures that were placed around burial mounds. These objects began as simple cylinders but evolved into intricate representations of houses, animals and human figures. Early cylindrical haniwa may have served as stands for offering vessels or as markers delineating sacred space[2]. As artisans’ skills improved, haniwa took on more detailed forms: houses with gabled roofs, horses complete with trappings and human figures sporting armour, helmets and elaborate hairstyles[2]. Why line a tomb with terracotta warriors and farm animals? Scholars propose several theories. Haniwa may have acted as protective barriers, warding off evil spirits from the tomb and its treasures. They might also have been companions for the deceased, providing comfort and status in the afterlife. Alternatively, haniwa could have been a form of ancestor worship, representing the extended community that supported the ruler in life. Whatever their purpose, these clay figures offer a fascinating window into Kofun‑period society. The variety of professions depicted – farmers, dancers, musicians, warriors – hints at a complex social structure. The sheer artistry of the pieces demonstrates a mastery of clay modelling and firing techniques unprecedented in Japan.
While the Yayoi produced functional, minimally decorated pottery, the Kofun people took ceramics to new heights. Using technology imported from Korea and ultimately from China, potters introduced the potter’s wheel for the first time in Japan[2][3]. This allowed them to create uniform forms with thin walls and high firing temperatures. The resulting Sueki (or Sue) ware was made of blue‑gray clay and fired in anagama kilns – single‑chamber, tunnel‑like ovens built into hillside slopes[3]. Sueki pieces often feature natural ash glazes produced by wood ash melting onto the clay surface. Later potters intentionally applied a green glaze, anticipating the jade‑like finishes of later periods. Sueki ware marks a turning point in Japanese ceramic history. Unlike the hand‑coiled, rope‑impressed pots of the Jōmon or the utilitarian jars of the Yayoi, Sueki was technically advanced and sometimes purely ceremonial. Many items were footed jars or shallow cups on tall pedestals[2]. These sleek, cool‑hued ceramics would influence later stoneware and porcelain traditions. Their introduction shows not only technological innovation but also continued cultural exchange: the potter’s wheel and kiln designs reflect contacts with the Three Kingdoms period in Korea and may have been brought by immigrant craftsmen seeking new markets.
Building enormous tombs is a team sport. Behind every mound were communities mobilised by charismatic leaders. During the early Kofun period, numerous uji (clans) jockeyed for power, forming alliances or waging wars much like the warring states centuries later. Each clan was led by an elder male who performed rituals to honour local gods and ancestors[4]. Beneath these aristocratic households were the be groups – occupational specialists including scribes, metalworkers, potters and papermakers. There were also enslaved peoples, often prisoners of war, who performed manual labour such as mound construction[4]. By the fifth century, one confederation of uji – known as the Yamato clan – began to dominate central Honshu and northern Kyushu. They did this through a combination of alliance building and military prowess[4]. Rather than conquer outright, Yamato leaders offered subordinate clans a share in the emerging political system. Those who refused faced coercion, but the emphasis was on integration rather than annihilation. The Yamato also welcomed immigrants from Korea and China, who brought valuable skills in metallurgy, weaving and writing. As the Yamato’s influence expanded, they began collecting tribute from subordinate territories and sending diplomatic embassies to China via the Korean peninsula, hoping to secure recognition and support[4]. Chinese records from this time mention the Five Kings of Wa who sent envoys to the Liu Song court between 413 CE and 478 CE[4]. These kings are believed to be Yamato rulers seeking titles and trading privileges. Meanwhile, Japanese envoys forged ties with the kingdom of Paekche, establishing an outpost in southern Korea that lasted until the Silla kingdom expelled them in 562[4]. Through these contacts, the Yamato gained access to new technologies (such as iron armour and writing systems) and reinforced their legitimacy by participating in the Sinocentric diplomatic order. As the Yamato polity consolidated, it also became more secular and military. Clan elders still performed rituals, but a budding bureaucracy began to manage land, collect taxes and organise labour for public works. The imperial line that would later rule Japan traces its roots to this period. By the end of the Kofun era, the Yamato clan had transformed from a loose confederacy into a kingdom with increasing control over population and resources.
The Kofun period marks the emergence of Shinto as a distinct religious tradition. The term Shinto translates roughly as “the way of the gods.” While its roots lie in earlier periods, particularly the Yayoi’s festivals and agricultural rites, the formalisation of Shinto rituals occurred during the Kofun[2]. Worship focused on kami – deities or spirits associated with natural phenomena such as mountains, rivers, storms and fertility, as well as revered ancestors and exceptional humans. Early Shinto did not require elaborate temples; sacred spaces were often open air – forests, waterfalls, even the mounds themselves. Rituals emphasised purity, offerings and the correct performance of ceremonies to maintain harmony between humans and the divine. Over time, clan leaders claimed descent from particular kami to legitimise their authority, a strategy the Yamato clan would adopt wholeheartedly.
As impressive as the burial mounds are, the Kofun period’s true legacy may be its role as a transition into recorded history. Archaeologists can date early Kofun sites by pottery and mound styles, but written records begin to appear toward the end of the period. The arrival of Chinese characters and Buddhism in the following Asuka period (538–710) ushered in a wave of cultural importation. By then, Yamato rulers were sending students and monks abroad to learn Chinese administration, law and religion. Yet these innovations rested on the infrastructure built during the Kofun: roads connecting regions, irrigation channels, craft workshops and centralised political power. Some tragedies may have accompanied this growth. The construction of giant tombs required immense human labour; many workers were likely conscripted from subordinate clans or enslaved groups. Rival clans who resisted Yamato authority faced punishment, and some families were forced to relocate or provide hostages to ensure loyalty. Yet compared to the bloody wars of later centuries, the Kofun conflicts appear relatively contained; power shifted through diplomacy as much as warfare. The absence of recorded famines or epidemics might be due to a lack of written sources, but it could also suggest that agricultural innovations kept populations stable. If nothing else, the enormous mounds stand as a testament to the resources the state could mobilise without collapsing under the weight of revolt.
Reflecting on our Yayoi story, we see that the Kofun period did not spring from nowhere. Wet‑rice agriculture continued to underpin society; without surplus rice, no one could have built moats around tombs or fired thousands of haniwa figures. Metalworking advanced from the bronze bells of the Yayoi to iron armour and weapons that cemented Yamato power. Social stratification deepened: while the Yayoi had emerging elites, the Kofun established clear hereditary classes, from uji nobles to be craftsmen to slaves. Even religious practices evolved rather than abruptly shifted. The festivals and animistic beliefs of the Yayoi matured into Shinto rituals centred on specific kami and clan ancestors. Yet the contrasts are just as striking. Where the Yayoi built villages of modest pit houses and raised barns, the Kofun period invested in monumental architecture that altered landscapes. The introduction of the potter’s wheel and anagama kilns revolutionised ceramics in a way earlier coil methods could not. And while Yayoi society was largely local, the Kofun world was outward‑looking, establishing diplomatic ties with powerful neighbours and importing new ideas. In many ways, the Kofun period is the hinge on which prehistory turns into early history, linking the innovations of the past to the literary and religious revolutions of the future.
The Kofun period offers a riveting chapter in Japan’s long saga. Its grand tombs and enigmatic haniwa captivate archaeologists and tourists alike. Its technological advances in ceramics and metallurgy influenced centuries of art. Its political innovations laid the foundation for the imperial state, while its religious practices gave shape to Shinto. By tying the period back to the Yayoi, we recognise that history is less a series of discrete boxes and more a continuum of cultural evolution. Standing atop a keyhole mound, one might imagine the bustling scenes below: potters spinning Sue ware on newly imported wheels, clay sculptors molding haniwa guardians, farmers flooding paddies with water from complex canals, and clan leaders plotting alliances over sake. The Kofun period was a time of monumental ambition and grassroots innovation—a combination that would propel Japan toward the Asuka era and the formal dawn of its recorded history. As we continue our blog series, keep your eyes on the horizon; those tombs hide not only ancient rulers but also the seeds of empires yet to come.