朱の世界4The Vermilion Road: From Ancient Cinnabar Networks to Kukai

The Gishiwajinden states simply that the Wajin painted their bodies with vermilion. From that brief passage an image of ancient Japan emerges that is beyond our ability to imagine. Centuries after that Chinese record, in the early ninth century, the monk famous as the founder of Shingon Buddhism, Kukai, began surveying Shikoku in search of Japan's ancient cinnabar. In a history that cannot be seen as isolated points, what deeper story lies behind the actions of this single monk? The grand narrative of vermilion in Japan remains shrouded in mystery.

What the distribution of mercury ore deposits stretching from Kyushu to the Kansai region tells us is this. When the value of cinnabar was first recognized and a turning point was reached, ancient Japanese people whose forms are invisible to us must have set out to survey for it. There are traces showing that by the late Jomon period a wide-ranging network for producing, processing, and distributing cinnabar had been established. But those traces represent a highly developed form, and we must consider the possibility that cinnabar had not attracted significant attention before that stage.

If we suppose that the arrival of new peoples seeking cinnabar set off a wave of prospecting across Japan, who were those people? Tracing this invisible movement does more than reveal the history of cinnabar. It connects to the migration patterns of ancient tribes across the whole of East Asia. Seen in hindsight, the unrecorded achievements of cinnabar discovery in this era laid the prototype for what would later become Kukai's Shikoku pilgrimage. The origins of the pilgrimage were not rooted in Kukai's devotion or ascetic practice. They were established by nameless people in pursuit of a mineral called cinnabar. Kukai performed the update. What circumstances linked these two eras?

Put another way, an ancient group may have been targeting cinnabar and undertaking large-scale migrations in pursuit of it. The initial recognition of value in cinnabar itself probably originated with the Jomon people, but the significance of that value most likely shifted over the course of the prospecting process. No single explanation suffices, but one possibility is the warding off of misfortune. Even today the torii gates of Shinto shrines are painted vermilion, though no longer with actual cinnabar. The color serves as a marker that the space beyond the gate is different from the world in which people live, and at the same time it functions to repel calamity and purify defilement. Whether this property was attributed to cinnabar itself or to the color vermilion as such is unclear. There are, however, traces suggesting that the raw materials for vermilion were deliberately distinguished in their use.

In ancient Japan there were three sources of vermilion pigment. Refined cinnabar, bengara (iron oxide red), and red lead. Historically it was cinnabar and bengara that achieved wide use. Bengara in particular is the oldest vermilion, with traces of use dating back to the Paleolithic period, and the great majority of vermilion pigment used during the Jomon period is believed to have been bengara. Around the middle Jomon period, however, refined cinnabar began to appear with increasing frequency in certain regions. In the Yayoi period that followed, some portion of cinnabar demand may have been met through imports from China. By the Kofun period the dominant pigment had returned to bengara and cinnabar use had become limited. In broad terms, across the three eras of ancient Japan known as Jomon, Yayoi, and Kofun, cinnabar was not being used in large quantities. Viewed from another angle, this can be read as a trace of how new beliefs and values brought by immigrant groups flowing into the Japanese archipelago transformed the use of vermilion on the Japanese side, more so than anything driven by the indigenous population.

The clearest trace of this is that certain groups deliberately distinguished between cinnabar and bengara in their usage. I do not yet fully understand the reason, but one plausible factor is that the distribution of cinnabar across the Japanese archipelago was limited, and the relatively abundant supply of bengara may have led to its widespread adoption as a pigment on a national scale. In the Tohoku region, where cinnabar is not produced, bengara was used as the pigment, and even when cinnabar flowed in from western Japan the preference for bengara did not waver. In northern Kyushu, however, which both contained cinnabar production sites and served as a major gateway for immigrants, cinnabar and bengara were being differentiated in use from an early stage. This differentiation did not originate on the Japanese archipelago. It was a practice that had already been established on the continent before the immigrants arrived. The tendency was most visible in the practice of sishu [施朱].

Sishu refers to the funerary ritual of applying or scattering vermilion pigment on coffins and the bodies of the dead. The practice existed in various forms around the world. In Japan sishu dates back to the Jomon period, but during the Yayoi and Kofun periods a distinctive custom appears in certain areas. Refined cinnabar was applied exclusively to the head and chest of the deceased, while bengara was used on the rest of the body. This singular custom is thought to have originated along the East China Sea coast of Kyushu and to have spread from there through the interior of Kyushu across the Seto Inland Sea region. In the course of this expansion, demand for cinnabar arose among the associated groups, though at this stage the bulk of the supply is believed to have come from Chinese imports.

This custom spread from Kyushu in western Japan through the Seto Inland Sea corridor all the way to the Kansai region, following a trajectory distinct from anything in eastern Japan. It has been established that by the time the construction of burial mounds for chieftains began to intensify in western Japan, this custom had already been incorporated. The expansion of the new practice accelerated. By around the third century, sishu was being practiced across an enormous area spanning all of western Japan except southern Kyushu, extending through the Kanto region and into southern Tohoku. It was in this process that demand for cinnabar surged. Not all of it was imported. Some was demonstrably domestic. This is the basic overview of what existed in ancient Japan. But there was in fact an era in which cinnabar demand increased even further. That era was the late Kofun period and the arrival of Buddhism.

In the late Kofun period the spread of new gilding techniques caused mercury demand to surge. Because mercury is a milky liquid it cannot be categorized simply as a raw material for vermilion. It can also turn black. And it can dissolve gold to form an amalgam and transform bronze to a golden color. The magical ability to turn bronze to gold captivated people, and after the arrival of Buddhism it dramatically altered the history of vermilion. The reason was that mercury was an indispensable material in the gilding process for Buddhist statues. As the casting of bronze Buddhist statues flourished, centered on Nara, the heartland of Japanese Buddhism, demand for refined cinnabar to produce mercury for smelting exploded.

From the historical traces the picture looks like this. If we confine ourselves to the three chronological axes of ancient Japanese history, Jomon, Yayoi, and Kofun, then cinnabar and bengara were used simultaneously in western Japan but bengara carried the greater overall weight. Cinnabar was used for limited purposes over a long span of time. It was the surge in demand following the arrival of Buddhism that changed this situation.

This does not mean, however, that the arrival of Buddhism created the cinnabar dynamic from scratch. It suggests rather that the groundwork had been laid over a long preceding period. There is one region that demands attention when examining the ancient history of cinnabar as the raw material of vermilion. That region is the Kikuchi River basin in Kumamoto Prefecture on Kyushu.

Scattered across the Kikuchi River basin are burial mounds of a type rare even by national standards, known as decorated tombs [装飾古墳]. Burial mounds (Kofun) are one form of funerary structure, and their historical evolution and typology are extremely complex. The era eventually came to be called the Kofun period in Japan, fitting into the sequence Jomon, Yayoi, Kofun. In reality, however, structures that might be called burial mounds were being built in earlier periods as well, and scholars differ on where to draw the lines. Among the many types of burial mounds, the vast majority of those classified as decorated tombs are concentrated in Kyushu, with a notable clustering in the Kikuchi River basin.

Decorated tombs are also called painted tombs. Their defining characteristic is the vivid polychrome patterns and images painted on the interior walls of the stone chambers and stone coffins. Archaeological estimates place their sudden appearance around the end of the fourth century. They reached their peak in the sixth century and continued to be built until around the seventh. The decline of decorated tombs is likely deeply connected to the arrival of Buddhism in the sixth century, and I personally believe it was closely linked to the rise of Buddhist statue production. At the same time we must not forget that the existence of cinnabar on the Japanese side had already been confirmed by the Chinese in the Gishiwajinden, well before the end of the fourth century. When we also consider the late Jomon cinnabar-related sites, this era should be understood as one in which new methods of use based on a new valuation of cinnabar emerged. It would be a mistake to conclude that cinnabar was of low value during the Jomon and Yayoi periods. Decorated tombs are broadly defined as burial mounds with painted interiors. The main concentration runs from Kumamoto to Fukuoka in Kyushu, but over time they spread beyond this zone, with outlying examples found as far east as Ibaraki and Fukushima prefectures.

According to the latest results published just last year, the total number of burial mounds classified as decorated tombs nationwide is 849. Of these, 448 are in Kyushu alone and 212 in Kumamoto alone. The Kikuchi River basin accounts for 131. In broad terms, Kumamoto holds a quarter of all decorated tombs in the country, with the Kikuchi River basin carrying a disproportionately large share. Following the new findings announced around May of last year I traveled through the Kikuchi River basin that summer. The development of decorated tombs in this region is factual, and it is possible that the immigrants and indigenous peoples of the Kyushu side refined this practice over time, honing it to its sharpest form in the north-central Kikuchi River basin.

What is intriguing is that the distribution of decorated tombs does not extend into southern Kyushu. It spreads from the north through the center. This suggests the existence of indigenous tribal groups in the south who did not adopt this funerary custom, and it speaks to a history in which the cultural sphere of decorated tombs was unable to penetrate southern Kyushu. The source of the decorated tomb tradition that expanded from there across western Japan was most likely generated by immigrants in northern Kyushu. Through a process of indigenization it reached the Kansai region. Viewed differently, it can also be read as the trace of specific peoples who had acquired this custom migrating toward the Kansai.

The existence of decorated tombs, as a funerary practice involving the use of vermilion, is an important factor that evokes the presence of immigrants in ancient Japan. With this perspective in place, the next question that arises is the identity of the principal agents who spread this custom. The invisible line that eventually reaches Kukai, born centuries later in Kagawa on Shikoku, might be called the vermilion road prepared in antiquity.