Lake Akan

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On the floor of a cold lake in eastern Hokkaido, in water the color of weak tea, green spheres lie in loose drifts and slowly turn. They are not stones and not eggs. They are alive — an alga that has wound itself into a ball, thousands of fine green filaments packed outward from a hollow center, velvet to the eye and soft to the hand, some no bigger than a marble and the oldest grown to the width of a spread palm. Nowhere else on earth do they gather like this. The alga is common enough in the northern hemisphere as a loose green fuzz on rocks; that it rolls into free spheres and carpets a lake bed in them is a thing of only a few places, and of one lake above all. This lake is called Akan, and the people who have fished and lived along its shore longer than any record reckon these green balls a treasure. Each October they gather the marimo up, pray over them, and carry them back down to the water — sent home, the way a guest is sent home, with thanks.

The caldera and its two mountains

Lake Akan — Akan-ko, 阿寒湖 — sits at about 420 meters above the sea in the Akan caldera of eastern Hokkaido, within Akan-Mashu National Park and, in the modern administrative map, within the city of Kushiro (Wikipedia). It is not a large lake, roughly thirteen square kilometers of surface, but it is deep for its size, dropping to about 44.8 meters, and its shape is the shape of fire and water at odds. The caldera is old; the lake in its present form is young by that measure, dating to roughly six thousand years ago, when volcanic activity threw up a lava dam across a valley and impounded the water behind it. Four islets stand in it — Ojima, Kojima, Yaitai, and Churui — and on Churui the lake keeps a small observation center where the marimo can be seen without disturbing the beds they grow in.

Two volcanoes stand over the water, and the Ainu names for them fix the pair in kin. To the northeast rises O-Akan, Mount Oakan, and to the southwest Me-Akan, Mount Meakan — the male Akan and the female Akan, the two mountains read as a couple presiding over the lake between them. Me-Akan is still active; O-Akan is the taller and quieter of the two, a near-perfect cone that the lake reflects on still mornings. To stand on the southern shore and look north across the water to that peak is to look at the arrangement the old names describe: a lake held between a man and a woman made of stone.

The name Akan is itself Ainu, and here the record must be honest about its own limits. The gloss most often repeated by outside writers reads the root as something like “unchanging” or “immovable,” but the Ainu language was written down late and largely by outsiders, the glosses vary from one authority to the next, and a place name worn smooth by centuries rarely surrenders a single clean meaning. What is not in doubt is that the naming is Ainu and old. Eastern-Hokkaido Ainu lived and fished around Akan long before any modern settlement took its present shape; the shore is a kotan, a village by the water, of long standing, and the records of the mid-nineteenth century already note Ainu houses along the rivers of the district. This is not scenery onto which a culture was later placed. It is a lived-in country.

The lake’s own heat helps explain why. The southern shore, where the Kotan stands, is a hot-spring town — Akanko Onsen — fed by the volcanism that made the caldera, and the warm ground that draws visitors is the same geological fact that gives the marimo their clear, gently stirred bay. The deeper human past of this eastern country reaches back through the fishers and hunters of the northern islands to the Jomon foragers whom scholars count among the ancestors of the Ainu — a continuity of life on Hokkaido that ran on, beyond the reach of the rice-and-tax order to the south, long after the mainland had become a world of paddy fields. The Ainu of Akan are the near end of that long line, and the lake is one of the places where it has never been broken.

Lake Akan and Mount Oakan (O-Akan), the ‘male’ Akan, seen across the caldera lake in December 2005. Photograph by コムケ (Komuke), via Wikimedia Commons. CC BY-SA 3.0.

The alga that rolls itself into a ball

The green spheres have a scientific name — Aegagropila linnaei, a filamentous green alga first described from a Swedish lake by Linnaeus in the eighteenth century — and a Japanese name that has traveled the world with them. In 1897 a student of the Sapporo Agricultural College, Kawakami Takiya (1871–1915), surveying the vegetation of the lake, found the balls in Shurikomabetsu Bay and gave them the name they now carry: marimo, from mari, a small round play ball, and mo, a general word for the plants that grow in water (MLIT, Japan Tourism Agency). Round water-plant: the name is a description.

The alga grows in three forms — free-floating filaments, a mat over rock, and the ball — and only in rare conditions does the ball form dominate and grow large. It needs a shallow, clear-bottomed bay where gentle, more or less constant water movement rolls the aggregates over and over, so that each sphere is lit and fed on every side and holds its shape. Lake Akan supplies exactly that, and supplies it at a scale found almost nowhere else: the marimo here grow to about twenty to thirty centimeters across, the largest known, and a study of the giant balls found that they are hollow-cored and can rise and sink with the light as photosynthesis fills their interstices with gas and then spends it — a body that breathes itself up toward the surface by day and settles again by night (Kato and colleagues, Scientific Reports, 2021). Large natural spheres of this kind occur in only a handful of lakes worldwide; the other well-known colony is in Iceland’s Lake Myvatn, where the balls stay smaller. Akan is the place where they grow to a hand’s width and blanket the floor of a bay.

A lake full of persons

To the Ainu, the indigenous people of Hokkaido, Sakhalin, and the Kuril chain, a lake like Akan is not a container of water and scenery but a dwelling-place of persons. The world of the visible — the bear on the mountain, the owl in the trees, the fish in the run, the fire in the hearth, and the water itself — is filled with kamuy, divine beings who live their own lives in their own country and cross into the human land, Ainu Mosir, clothed for the visit in a body that people can see. A kamuy who comes as a bear wears the bear’s shape as a guest wears his good coat; the meat and the pelt are the gift he brings, and in return he is owed honor — prayer, the shaved-willow inaw, a share of the ritual drink — and then he is sent home, satisfied and well-treated, so that he and his kind will come again. It is not nature-worship and not a fear of the woods. It is a moral economy of hospitality between two peoples, one human and one divine, each with obligations to the other.

Within that world the marimo are held in unusual regard, and the clearest window onto how is the festival built around them. The Marimo Matsuri, begun in 1950 and led by the Ainu of Akan, runs three days each October and frames the conservation of a fragile alga in the tradition’s own grammar of welcome and return (Japan National Tourism Organization). On the first evening the marimo are welcomed: a torch procession, the taimatsu-gyoretsu, winds through the lakeside town by firelight, several hundred people carrying torches, and the marimo are received as honored guests are received. On the closing morning, after a kamuy-nomi — a prayer to the divine spirits, performed by Ainu who gather from across Hokkaido — the balls are carried in procession back down to the shore and returned to the lake. The logic is the logic that governs the sending-home of any kamuy: a being that has given something to the human world is thanked, honored, and released to the water it came from, so that it will remain and flourish. The rite is public and much-photographed, and its meaning can be told plainly from outside — the welcome, the prayer, the return — without pretending to the inner detail that belongs to those who conduct it.

That the grandmother of the hearth-fire, Ape-huci-kamuy, attends where the Ainu gather and pray is part of the same understanding: she is the first kamuy addressed at any ceremony, the one who carries the words of people up to the other divine persons. A prayer over the marimo is not spoken into empty air. It is spoken into a lake that is, in this reckoning, thoroughly inhabited.

Marimo (Aegagropila linnaei), the velvet-green algae balls of Lake Akan, shown at the Akankohan Eco-Museum Center on the southern shore, March 2005. Photograph by コムケ (Komuke), via Wikimedia Commons. CC BY-SA 3.0.

The kotan on the southern shore

The living settlement that keeps this practice took its present shape within living memory, and its founding is a plain matter of record. Much of the land around the lake belonged to the Maeda Ippoen estate, and in and after 1959 its third-generation head, Maeda Mitsuko, offered private land free of charge so that Ainu families, scattered and hard-pressed, could relocate together and go on making their living by their craft (akanko-ainukotan.com). The Ainu of Akan remember her as the “mother of Akan.” Around that gift the Akanko Ainu Kotan grew into the largest Ainu settlement in Hokkaido — some thirty-six households and roughly a hundred and twenty residents by the late 2010s — a working town of carvers and weavers and dancers rather than a preserved village behind glass (Akanko Ainu Kotan, official).

Craft is the daily substance of the place. The men carve — bears, owls, the ceremonial ikupasuy, and small figures in blackened wood — and the women embroider the bold curvilinear patterns, the moreu and aiushi, that run in appliqué and thread along the borders of a garment to guard the openings where harm might enter. Carvers came to Akan from across Hokkaido and sharpened one another’s work, and the Kotan became a center where the crafts were not merely kept but pushed. Above the shops, and above the crafts, stands the dance.

The Akanko Ainu Theater “Ikor” — ikor, a treasure — was the first theater in Japan devoted to Ainu performance, an indoor hall built around a stage with a real fire at its center and an artificial stream, so that the ceremonial dances are performed in something like the setting they belong to, in the presence, the tradition holds, of the hearth-fire grandmother and the kamuy of the place (HOKKAIDO LOVE!). What is staged there is not invented spectacle. The old ceremonial dances of the Ainu — the crane dance, the bow dance, the sword dance, the swaying black-hair dance of the women — were inscribed by UNESCO in 2009 on the Representative List of the Intangible Cultural Heritage of Humanity, and Ikor is one of the living houses in which they are danced. The theater also carries them forward into new work: Lost Kamuy, a piece that sets the UNESCO-listed ceremonial dance against digital art and contemporary choreography, has taken the tradition to audiences who would never climb to a lakeside hall in eastern Hokkaido.

Protection, dispossession, and a present-tense center

The marimo drew the outside world’s attention early, and nearly loved it to death. Once the balls were known, they were collected as curios and souvenirs and the beds were quickly depleted; the response was legal protection, first as a Natural Monument in 1921 and then, at the highest tier, as a Special Natural Monument of Japan in 1952 (MLIT, Japan Tourism Agency). The community-led Marimo Festival, begun in 1950, grew out of the same crisis of over-collection — a conservation movement that chose to speak in the language of the tradition rather than the language of the statute, welcoming and returning the alga rather than merely fencing it off. The two registers, the Special Natural Monument and the October rite, protect the same green spheres from two directions.

The Kotan’s own founding sits inside a longer and harder history, which belongs in full to other places and is only touched here. The Ainu were recognized as an indigenous people of Japan in law only in 2019, following a Diet resolution in 2008 — the closing turn of the long assimilation era whose earlier instrument, the 1899 Hokkaido Former Aborigines Protection Act, branded the Ainu kyudojin, “former aborigines,” and set out to dissolve their language, their women’s tattoos, and their ceremonies into the surrounding state. The full account of that suppression and the legal recovery belongs to the Saru valley, where a court first recognized the Ainu as an indigenous people, and to Nibutani; the account of the national revival belongs to Upopoy, the national museum and park at Shiraoi that opened in 2020. What that history explains here is a single word in the Kotan’s own story: that Ainu families were “scattered” and hard-pressed by 1959 was not an accident of fortune but the residue of a century of dispossession, and that a private land gift was what let them gather again is a measure of how little the state had left them.

Today Akan is among the most visible living Ainu places, and it is read, increasingly, on its own terms. In 2023 the National Ainu Museum at Upopoy devoted a seasonal exhibition to the region — akanto un kotan, “the kotan at Akan” — mounted in cooperation with the Akan Ainu associations and preservation society, tracing the district from the mid-nineteenth-century houses along its rivers to the crafts and performances of the present. It presented the Ainu of Akan not as a vanished people whose relics survive but as makers still at work, a distinction the whole shore insists on. The marimo help make the point. An alga that grows to a hand’s width in almost no other water, tended for a century by the people of one lake and each autumn carried down to it again with prayer, is not a relic and not a curiosity in a bell jar. It is a guest in a lake full of persons, welcomed by torchlight and sent home to the water — and the town that welcomes it is a town of the living.

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