Kukai and the Road of Vermilion: Cinnabar, Mercury and the Shikoku Pilgrimage

The seven years in which Kukai vanishes from the record are among the great riddles of Japanese history. Before his journey to Tang China, he is simply absent from every document.

And there is a stretch in the life of this central figure of Japanese history about which nothing at all is known: the "seven lost years," from 797 until he sailed for Tang in 804.

Indeed, not a word about these seven years appears in the biography Kukai wrote himself, and none in the court's records. He may well have been involved in a top-secret undertaking under the emperor's direct control.

After seven mysterious years, then, Kukai appeared suddenly with ample funds and outstanding command of the language, crossed to Tang, and in two years understood the secrets of esoteric Buddhism more deeply than anyone.

Kukai's image as the most famous monk in Japan is so strong that one thing goes unnoticed: what he learned from Otari was not Buddhism. It was Confucianism.

In these years Kukai studied the Chinese classics that samurai of the Edo period would later learn as part of their education. They centered on the Analects of Confucius, the Classic of Filial Piety, and the Zuo Zhuan, and reached as far as the techniques of composition.

To put it plainly, the Ato are very likely a clan that came out of the Mononobe after the Mononobe fell.

And the important point is that Kukai's mother came from the Ato, and his father is taken to be a man named Anto no Chitoku (安斗智徳).

Yet Kukai was unknown in Buddhist circles and came from no wealthy family. How did he come to have so much money? That is still a mystery.

It is guessed that the success of that secret project earned him enormous funds and the backing of Emperor Kanmu and the court, and that this is how he became, exceptionally, a member of the mission to Tang.

For Kukai to be chosen once more as an exception, in 804, as a student monk in the mission to Tang China, was not realistic without strong support from the rulers of the new Heian-kyo. Put another way, without the backing and support of the forces at the core of the move to Heian-kyo, a man like Kukai could never have crossed to Tang China with that mission.

My own view is that the one who first noticed Kukai was not Kanmu but the Hata, who were using their wealth to aim at taking hold of the next hegemony.

Ten years later, in 804, he was chosen as a member of the mission to Tang China, a project of the state.

The pilgrimage is tied to Kukai in the mind, and the reality is unknown.

To put it plainly, the true reason Kukai opened the pilgrimage is unknown.

Today he is joined in the mind with Koyasan and with the striking world of becoming a Buddha in this very body, and the image is heavily exaggerated.

To my own mind, the henro feels less like a product of pure faith and more like the traces of a reconnaissance mission that later generations romanticized through a religious lens.

Mercury (cinnabar) deposits are scattered across the Japanese archipelago, and to this day, the places where they are found frequently bear names containing the characters for Niu (丹生). Archaeology has confirmed the deep link between ancient place names or shrines named Niu and the presence of cinnabar. I have visited several Niu shrines and sacred sites myself; in such places, cinnabar was mined from antiquity, and a distinct religious tradition grew up around the extraction of mercury.

Seen in this light, a broad look at Japan's major cinnabar-producing regions reveals why Kukai laid out the pilgrimage route in Shikoku and established his base on Mount Koya. The key geological feature here is the Median Tectonic Line. The largest fault zone in Japan, it runs east to west through the center of the archipelago, stretching roughly 1,000 kilometers from Kyushu to the Kanto plain.

Wakayama was linked to the court by land routes, and Tokushima by sea. When we set faith aside for a moment and look at the practical demand for resources, the hidden intent behind Kukai's Shikoku pilgrimage and his opening of Mount Koya comes clearly into view.

Vermilion pigment made from mercury was used in vast quantities to paint Buddhist scrolls and temple halls, and mercury itself was essential for amalgam gilding — the process used to give Buddhist statues their radiant golden skin.

The prime example is the Great Buddha (Vairocana) at Todaiji in Nara. When the colossal statue was first completed, an astronomical amount of mercury was consumed to plate it in gold. According to historical records, roughly 437 kilograms of gold required some 2,459 kilograms of mercury — a ratio of 1 part gold to 5.6 parts mercury.

Here lies one of the keys to unlocking the mystery of Kukai: while mercury had been prized in Japan since ancient times as a miraculous medicine, demand for it surged dramatically with the flourishing of state Buddhism.

The magic of turning bronze to gold captivated people, and after the arrival of Buddhism it changed the history of vermilion greatly, because mercury was an indispensable material in the gilding of Buddhist statues. Once the casting of bronze Buddhist statues flourished, centered on Nara, the true home of Japanese Buddhism, the demand for refined cinnabar for smelting mercury exploded.

This does not mean that the arrival of Buddhism made the course of cinnabar. It suggests that things had been prepared, over long years, before that.

The Gishiwajinden records, in a single brief line, that the Wajin painted their bodies with vermilion. From that line comes a glimpse of an ancient Japan we cannot imagine. Centuries after that Chinese record, in the first half of the ninth century, Kukai, famous as the founder of the Shingon school, began to survey Shikoku in search of the ancient cinnabar of Japan.

The torii, the gate of a shrine, is still painted vermilion today even where no cinnabar is used, as a sign that beyond it lies a place different from the world where people live, and also to ward off misfortune and purify defilement.

In Japan sishu exists from the Jomon period, but in the sishu of the Yayoi to the Kofun period a characteristic custom appears in some regions: refined cinnabar was applied only to the head and chest of the buried, and bengara to the rest. This singular custom is thought to have begun on the East China Sea coast of Kyushu and to have spread from there, through the interior of Kyushu, across the Seto Inland Sea.

The custom spread from Kyushu in western Japan, by way of the Seto Inland Sea, as far as the Kansai, a movement different from that of eastern Japan.

According to the latest results, published just last year, the total number of tombs counted as decorated tombs in the whole country is 849. Of these, 448 are in Kyushu alone, 212 in Kumamoto alone, and 131 are packed into the Kikuchi River basin. Broadly speaking, a quarter of the decorated tombs of the country gather in Kumamoto, and the Kikuchi River basin holds a large share of them. After the new announcement around May last year, I went around the Kikuchi River basin that summer.

In the end, the discovery of cinnabar in this unrecorded age can be said to have laid down the prototype of Kukai's Shikoku pilgrimage. The origin of the pilgrimage was not Kukai's faith or his training. It was set up by nameless people who pursued a mineral called cinnabar, and Kukai carried out the update.

The unseen line that ties all the way to Kukai, born later in Kagawa in Shikoku, may be called a road of vermilion prepared in antiquity.