The Chashi: Symbols of Commerce and Conflict in Japan Frontier North
By Justin Randall
Edited by Tomoko Irie
The Tokoro River flows quietly into the choppy tides of the Sea of Okhotsk. Near its mouth, nestled among groves of lush Hokkaido green, a few unassuming knolls convey the secret history of Japan’s northernmost indigenous peoples. These knolls, once chashi, which translates to fort or palisade, number in the 500s across the breadth of Hokkaido. They are often positioned along key trails or waterways, such as in the instance of Tokoro, or upon cliffs, as in the cluster of chashi on the cliffs in Nemuro. These chashi tell the story of the growing relationship between Japanese and Ainu commerce and, at its apex, boiling over into open conflict. It remains now as an important resource to learn the history of Japan’s northern peoples.
The Ainu, one of Japan's indigenous people with a rich cultural heritage centered in Hokkaido that dates back thousands of years, have faced historical marginalization and significant challenges, especially during the Japanese expansion. Yet, when studying the indigenous cultures in Hokkaido, the prime frustration is the lack of written materials, with the Ainu language itself isolated among humanity’s great tapestry and presently endangered. Therefore, connecting the nodes of understanding of the Ainu, and its preceding cultures, means looking below the earthworks for clarity.
The Beginnings of Chashi
In Hokkaido, time and its stretches are measured differently than in southern Japan, reflective of tribes and groups that lived among the wide open plains of the east and narrow foggy volcanic valleys of central and southern Hokkaido. Concurrent with the Kofun and the Yayoi period is the Epi-Jomon period followed by the Okhotsk, Satsumon, and Tobinitai cultures. Hokkaido’s trinity of hunter-gatherer cultures appears in the wake of the Epi-Jomon period between the 5th and 12th centuries. Okhotsk’s influences drifted in from the north, the Satsumon from the south, and later the more isolated Tobinitai arose from the east. Okhotsk and Satsumon border each other roughly geographically and historically, and it is from this connection that the Ainu culture was born, separately from the Japanese in the south.
One integration from the preceding cultures was animism, most notably the bear-cults of the Okhotsk cultures. This phenomenon was not present within Satsumon communities but apparent in later Ainu cultures in the form of the iomante ritual. For the Ainu, the gods, or kamuy, are represented across the natural world in both animate and inanimate objects. One such kamuy, represented within the mighty Hokkaido brown bear, played a large role in Ainu spirituality and their “sending back rituals.” A cub raised in captivity as a young cub would be sacrificed ceremonially back to the afterlife which was thought to be the home of the kamuy as opposed to mosir the earthly realm. Okhotsk culture pit dwellings feature the remains of the bears in ritual objects of worship. The later Ainu chashi was considered a gathering place for rituals such as the iomante.
Rituals like these were held near villages, or kotan, well within the domain of the tribes. The chashi were also positioned near hunting or resource-rich areas, often taking advantage of nearby terrain to enhance defensibility or to project power. Researchers note five broad categories of shape and size: hilltop, cliff face, summit, island, or flat. Hilltop chashi were formed at the end of a narrow hill with a moat protecting the widest section of the fort. The cliff face chashi situated the end of the structure on a wide cliff looking down with moats cornering off on three sides. Summit chashi sat at the top of a hill with moats on all sides and was similar to an isolated island. Flat style chashi occupied unelevated lands with moats on one or more sides, such as Tokoro’s chashi featuring an L-shaped moat surrounding it.
On the grounds of the Ainu chashi, remnants of both Okhotsk and Satsumon culture, namely tools and pottery, have been found within the remains of pit dwellings. Defined by the carvings made with brushlike tools, Satsumon pottery for both practical and death ritual usage was commonly found. These features are largely absent from the Okhotsk style of pottery which emblazoned the tops of their stoneware with long string-like patterns. Both styles of pottery fell out of fashion as the nascent Ainu identity came to the forefront, giving rise to the Ainu kotan and chashi living as opposed to the previous generations of pit-dwellings.
Growing Domains and Growing Tensions
The rise of chashi construction is inextricably linked to the growth of trade between Honshu (main island Japan) and Hokkaido. While the chashi entered the archaeological record in the 14th century, their construction sharply increased during the 16th and 18th centuries as trade became the chief interaction with southern Japanese, who were slowly expanding north. This expansion was fueled by demand for furs, fish, and other natural resources not widely available in Honshu, which were prized possessions. Chashi became important for managing trade routes, ensuring access to prime lands for commodities for trade, as well as, the subject of raids by rival bands in search of wealth or resolutions to disputes over it.
Under the Tokugawa shogunate, trade with the Ainu was monopolized under the Mastumae clan in southern Hokkaido, which at that time was referred to as Ezo. Trade became lucrative among the Ainu populace. Bear furs and meat, salmon from Hokkaido’s many rivers, and rarer commodities such as birds like hawks and red-crown cranes fetched high prices. As the value of commodities rose, infighting between bickering chiefdoms of Ainu rose in tandem. Ainu society was stratified on local and regional levels with the most basic unit being the household, or chise, followed by the village kotan and the largest group being the river group, or shine-itokpa, which consists of several kotan-sized groups bound loosely by geography or shared tribal history.
When river groups' economic interests collided, the ensuing conflicts involved small skirmishes or massacres protracted until semi-regional warlords brokered peace between parties. Control over commodities brought the ability to cement power among a coalition of tribes through resources from the south or the image of wealth. Chashi projected power across wide areas and served as meeting places for diplomacy and festivity between tribes. Conversely, groups often clashed at chashi in search of goods or to evict the current tenants and steal their goods to trade south.
While the growth of chashi and commodity culture increased, Japanese influence to the south soon became a more existential threat, as they sought to exert more control outside of their domain.
When Trade Expansion Turns to War
Up until the mid to late 1600s, the Matsumae clan, a samurai clan from Honshu, only occupied the southernmost areas of Hokkaido, near modern-day Hakodate. In contrast to the Ainu’s ambiguous borders, the Matsumae domain segregated itself away from the Ainu territories and forbade entrance to the Ainu without express legal permissions.
However, further trade relationships between the Matsumae and the Ainu grew one-sided in favor of the shogun and his fiefs. Matsumae then created a policy that lumped the Ainu into two rough categories based on geography. It divided Hokkaido diagonally from the location of modern-day Sapporo to the Shiretoko peninsula into the West Ezo (Sea of Japan coast) and the East Ezo (Pacific Ocean coasts). These groups often quarreled over hunting grounds and commodities or fell under the spheres of influence projected by warlords, until grievance incurred by the Matsumae succeeded in unifying different regional bands under the fear of open conflict or assassination by the Matsumae.
One regional lord, Shakushain, quarreled over trade and historical rivalries with the neighboring Onibishi. Bad blood soon began to boil and the death of one of Onibishi’s clansmen in 1667 ruined the peace. Onibishi and others sought diplomatic back channels to sue for peace. Shakushain took the initiative killing several of Onibishi’s family members and eventually tracking down the patriarch and killing him. Onibishi’s remaining fighters were forced to vacate their lands on the Shibuchari river and reconstruct their chashi higher in the mountains. In retaliation, the remnants of the Onibishi waged a war and burned down the Shakushain’s chashi on the Shibuchari River.
What specific motivations that forced Shakushain to violence against Onibishi are lost to history. As by the 1600’s and the 1700's, the only written sources were those recorded by Japanese chroniclers. As the Ainu generally passed their important traditions and legends down orally through the yukar, the specific thoughts and emotions of leaders have eroded, much like the chashi, against the winds of time. What the chronicles do report is the cunning of Shakushain, in the aftermath of this dispute, to bring about a sort of pan-Ainu unity against the Matsumae.
Utou, one of Onibishi’s remaining followers, appealed to the Matsumae for intervention in the dispute through material support. Turned away empty handed, Utou returned to the lands still controlled by his allies, only to succumb to small-pox along the way. Whispers of his assassination soon became widespread, allowing for Shakushain to appeal to the other Ainu chiefs to unite against the Japanese. Shakushain's revolt began with attacks across Hokkaido, and in a short span of time, over 150 Japanese were killed in East Ezo and another 120 killed in West Ezo. The scale of the killings took the Matsumae by surprise and they quickly appealed to the Shogun for aid.
The Tsugaru clan in northern Tohoku, likely keen on wrestling the Shogun’s favor away from the Matsumae and usurping the Ezo monopoly, came to their aid. The Tsugaru sent several hundred soldiers north under the condition that the Matsumae forces led all interaction between the Ainu and Japanese. War had begun, but would come to its conclusion three years later, as the pan-Ainu resistance was gradually overpowered by superior weapons (guns) and death threats. Shakushain himself was tricked into surrendering, leading to his assassination and the burning down of his chashi. And thus, the pan-Ainu resistance met its end. Shakushain’s efforts marked the last major conflict in Ainu-Japanese relations. As time advanced, the Japanese ensured greater control of the island and facilitated where and when Ainu hunted or fished. In the following centuries, chashi construction ceased as Ainu resistance was neutered and commerce was fully integrated into Japanese control.
The Future of the Ainu Chashi
Once palisades are now markers of a history near-forgotten. The chashi are being utilized as a window into the past. Through the conservation of the ruins, a wealth of archeological treasures has been pulled from the earth. Chashi are not only helping to educate the public about Ainu history but also contributing to the revival of Ainu culture and the promotion of sustainable tourism. In Tokoro, efforts are being made to return the chashi to its original form. Elsewhere, in Hidaka you can learn about Shakushain in greater detail at the Shinhidakacho Ainu Folk Museum. These forts hold the potential to become key destinations for cultural exploration, fostering greater understanding and appreciation of Ainu heritage for generations to come.
About the Author: Justin Randall is a writer and photography currently working as part of the Regional Revitalization Corps in Kitami City, Hokkaido. A dosanko at heart, Justin has spent his entire life in Japan in the great outdoors of East Hokkaido with no intention on leaving. A frequent contributor to newspapers and travel sites alike, Justin hopes to enrich the reader with local perspectives and legends.
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