This article appeared in Tokyo Weekender Vol. 1, 2025.
To read the entire issue, click here.
Between approximately 300,000 and 90,000 years ago, a series of four massive volcanic eruptions shaped what is now the Aso caldera — one of the largest on Earth. It extends approximately 17 kilometers east to west and 25 kilometers north to south and contains Mount Aso, an active volcano with steaming craters, as well as vast grasslands where cattle graze.
Legend has it that in ancient times, a god split open the caldera’s rim, allowing dammed-up water to escape and create the fertile plains that ring the volcanic crater. The citizens of Aso city call this mystical caldera home. Surrounded in every direction by cliffs that rise as high as 700 meters, the landscape gives those who enter a sense of stepping into a vast celestial diorama — so small, yet watched over by some larger being.
The constant smoke billowing from Mount Aso’s highly active peak, juxtaposed against the vast expanse of greenery, lends the city an otherworldly energy. It’s a fascinating place to experience the majesty of nature in all its forms, from bucolic swaths of grasslands to violent plumes of volcanic smoke.
Volcano City
Aso is characterized by the presence of Mount Aso, one of the most active volcanoes in the world. (It last erupted in 2021.) The volcano consists of multiple peaks, and its many viewpoints are accessible by car or on foot. However, access to Nakadake crater — its most active and dynamic vent, known for its steaming, turquoise-colored acidic lake — is restricted when gas levels become dangerous or when volcanic activity intensifies. The city highly recommends checking the volcano’s current status before visiting.
The most popular ways to visit Mount Aso are by driving to the easily accessible crater-viewing area or by hiking one of the many trails that wind through the caldera’s scenic landscapes, including one that leads to the peak of Mount Nakadake and offers a spectacular view of the active crater below.
For visitors wanting to make the most of their volcano-viewing experience, helicopter rides offer a view of the mountain from above. One company, Jet Heli Service LLC, departs from a local zoo called Cuddly Dominion. It has a few different flight options, and its most popular course will take you on a seven-minute loop around the whole Nakadake crater, allowing you to peer into the fuming waters at its center. There are other ways to view Mount Aso from on high as well: As long as weather conditions permit, visitors can ride in a hot air balloon or paraglide, both through guided experiences offered by the outdoor activity shop Aso Nature Land.
A Cycle of Rebirth
The Aso grasslands are a sight to behold year-round: verdant in summer, a pale gold expanse of Japanese pampas grass in autumn, snowcapped in winter — and then torched and returned to ashes to welcome the multicolored rebirth of spring.
This unique region is maintained through noyaki, or controlled grassland burning. Every year, as winter comes to a close, select parts of the Aso grasslands are set ablaze, leaving behind a black expanse of ashes. From this desolate-seeming landscape, the rare Oriental yellow violet blooms in profusion, dotting the black terrain in a constellation of gold signaling the seasonal renaissance.
Noyaki is a 1,000-year-old tradition started by early settlers in the region to promote the growth of new grass for cattle, kill pests and prevent the overgrowth of trees. Beyond its agricultural purpose, this practice holds significant environmental benefits. By maintaining the open grasslands, noyaki helps preserve Aso city’s unique ecosystem; it also encourages biodiversity, as the fresh growth attracts insects and small animals. Moreover, the controlled burn helps reduce the risk of large-scale wildfires, as it removes dry, combustible materials. The practice also prevents the encroachment of forests, ensuring that the wide, expansive vistas of Aso remain intact.
The grasslands can be enjoyed on foot or by car, but an exciting alternative is to explore the sprawling area on horseback. The Yume Daichi Green Valley ranch offers tours around the grasslands that are safe for beginner riders, with attentive instructors providing guidance before and throughout the experience. Feeling the sturdy warmth of an animal allows visitors to feel more connected to the expansive land before them.
Cycling tours are also an excellent way to see Aso. Book a bokuya (pastureland) ride for a guided biking experience that will take you through the city’s grasslands, including areas that are normally off-limits to the public. Unlike standard routes, a bokuya ride leaves the main roads behind, ushering you instead into open pastures where you’ll follow trails that locals have used for generations. Included in the rate is a grassland conservation fee, which helps with environmental preservation.
Born from a volcano with lands that return to ash at the end of every winter, the city of Aso has a mythic quality to it — like a phoenix, burning and resurrecting each year. Whether you’re exploring its volcanic craters, cycling through its vast pastures or connecting with its ancient traditions, Aso provides a profound and awe-inspiring experience. It’s a place where nature’s raw power and human tradition coexist, where the land is constantly reborn and where visitors are invited to witness and be part of a living, breathing landscape.
Learn more about Aso city and plan your visit at the Aso official website.
