古代山陰の謎（古代出雲 その1）Unlocking Ancient Japan's Mysteries in San'in
Over this past week I went around Hiroshima, Omishima, Okayama, Tottori and Shimane and carried out various surveys from Setouchi to the San'in region. The aims of this trip were to explore ancient Japanese history, Mingei, and the sharp Confucian scholars of the Edo period, and what taught me most was the reality of the San'in region in ancient Japan.
San'in means the Sea of Japan side of Tottori and Shimane. In the West it is hardly known apart from Izumo Taisha in Shimane and the Tottori Sand Dunes, famous as tourist sites, and it is a region that draws little attention. It is hard to imagine, since the region has declined extremely today, but in ancient Japan it was one of the most important regions. So if readers interested in ancient Japanese history travel to Japan, I recommend going to San'in.
Despite that long history, the academic fields that developed through the twentieth century, such as archaeology, have basically not made much of San'in, so it is still wrapped in many mysteries. I will present this in two parts.
San'in was an important stage of the three periods of ancient Japanese history, Jomon, Yayoi and Kofun, and because the cultural spheres of various peoples mixed and took shape in complex ways, it is not easy to grasp its reality. First, looking at San'in's geography, it is close to northern Kyushu, the main gateway for routes from China and Korea in ancient Japan, so foreign culture evidently influenced it at a relatively early stage once it flowed in. Beyond that, we must also consider that quite a few groups came directly to San'in at the time without passing through northern Kyushu.
San'in also functioned as a singular place where the cultural spheres of many parts of Japan gathered, not only those of foreign influence. Today's Japan has many cities on the Pacific side, such as Tokyo, Osaka and Nagoya, and an overwhelming population, which is overlooked, but Japan once had many cities on the Sea of Japan side, where wide-ranging trade went on by sea routes and flourished greatly. Active there were the tribes who traveled the sea. In the area of Munakata and Shikanoshima in northern Kyushu, two different tribes skilled in navigation existed in the Jomon period, and trade expanded as they spread across the country.
San'in flourished greatly especially in the Yayoi period, but this is a new understanding of history that has been coming to light only in the last thirty years or so. Before that, San'in and the Yayoi period were thought to have almost no connection. Strangely, however, when the Kofun period began, the San'in region declined, the San'in people themselves erased many of their traces, the main stage of history moved to the Kansai region, to Nara and Osaka, and after that the axis shifted to Kyoto. San'in hardly appears afterward in important Japanese history, so its whole picture has still not been clarified.
Because San'in has Izumo Taisha in Shimane, one of the oldest shrines in Japan, research there was originally concentrated on the Jomon period. This is because, from long ago, traces of a huge power with Izumo as its stage have been supposed in the myths recorded in the Kojiki and Nihon Shoki, and because no major Yayoi finds had been made in San'in. It was therefore widely held that the power of San'in, headed by Izumo Taisha, grew greatly in the Jomon period, and that the Yayoi period and later were probably not so important.
From the end of the twentieth century into the early twenty-first, however, this view of history was overturned. A number of coincidences combined, and Yayoi sites and artifacts that upset the established view of archaeology were found one after another, forcing a major reconsideration of ancient Japanese history.
What is newly drawing attention now is the possibility that ancient Izumo in the Yayoi period had the largest kingdom in Japan at the time. Lake Shinji today is a huge lake 45 km long, spread around Matsue in eastern Shimane, but it once extended as far as Izumo in the west, and south of Izumo Taisha on the Sea of Japan coast, another huge lagoon, Lake Jinzai, connected to the Sea of Japan, is known to have existed.
Looking south from the torii at the entrance to the shrine grounds of Izumo Taisha, called “Seidamari” (勢溜), you see Shinmon Street (神門通り), lined with shops for tourists, and if you look closely you can see that the street descends steeply to the south. That is, Izumo Taisha was built in hill country, and below it was originally a lagoon. In fact, whatever topographical data one consults, only the site of Izumo Taisha has been land since the Jomon period. This suggests that Izumo Taisha was the gateway to the inland San'in of ancient times and at the same time an important strategic point.
An old legend handed down among the priests of Izumo Taisha says that the main hall of the ancient shrine was far larger than now, and was said to have been as high as 48 m. The present main hall is the tallest among Japanese shrines, but at about 24 m it is almost exactly half. Because it had already shrunk to its present size by around the Edo period, whether this was mere legend has been debated hotly. In the modern era scientists increasingly took such legends to be fantasy, and since no firm evidence was found, it was ignored and forgotten.
In 2000, however, the situation changed. Incredibly huge pillar remains were unearthed by chance near the main hall of Izumo Taisha. They matched completely the old plan of Izumo Taisha that the family serving as chief priests had handed down for generations, and people were astonished to learn that it was not mere legend. Dating also matched the record that Izumo Taisha was rebuilt in 1248, in the Kamakura period, proving that a very large structure existed as early as the thirteenth century. The pillar remains can be seen at the Shimane Museum of Ancient Izumo, opened next to the shrine.
Because this discovery is only partial, older traces from before the Kamakura period are presumed to remain buried in the grounds of Izumo Taisha even now. And this great discovery sharply raised interest in the high-rise shrine of ancient Izumo. The high-rise shrine of ancient Izumo is a structure without parallel anywhere in the world, and there may have been people in Izumo with advanced technology of their own.
At the entrance of the main sea route into Shimane from the Sea of Japan, then, a huge high-rise shrine once stood. With no obstacles around, people who came to Izumo over the sea since ancient times would have seen this huge shrine clearly. Its function is uncertain, but if it was a Yayoi-period shrine, it would have been a landmark for those coming from Korea and China, and from the many regions of the archipelago, and at the same time a “kekkai” (結界), a barrier to deter invasion. Such invisible, spiritual belief is one of the characteristics of the Yayoi people.
Interestingly, the traces of the prosperity of ancient Izumo can still be felt. It is the Kamimukae-sai (神迎祭), the oldest Shinto rite in Japan, held at Izumo Taisha for about a week from the 10th day of the 10th month of the old calendar, when the gods of every part of the country gather. In the Kamimukae-sai, countless gods come to Izumo by boat over the sea. At dusk the priests light a fire on the shore of Inasa no Hama, west of Izumo Taisha, welcome the arriving gods, guide them to Izumo Taisha and entertain them for a week.
Incidentally, the Japanese still call this month in the old calendar Kannazuki (神無月), an old word meaning “the month without gods,” because the gods of each place go to Izumo and are absent from many lands. In Izumo, by contrast, because the gods gather, it alone is called Kamiarizuki (神在月), “the month with gods.” Old Japanese names thus convey the “truth” of ancient times to us.
What kind of world was ancient Izumo? Its romantic reality of long ago is gradually coming to light through vast amounts of research. I will write about that next time.