Sacred Springs, Samurai Spas, and the Evolution of Onsen in Japan
By Thomas Shomaker
Japan is a nation forged by fire.
Lying atop the convergence of four tectonic plates, the country’s islands rose out of the sea as a volcanic chain and still precariously float above deep reserves of magma. While quintessential icons like the active volcano and sacred symbol of Japan, Mt. Fuji, might grab immediate attention as a cultural product of the country’s origins, natural geothermal springs gushing with hot mineral water, known as onsen, are just as representative of Japanese culture and customs.
The Japanese government sets the definition of onsen as a natural spring with waters of at least 25 degrees Celcius at the venting source. The hot spring water must also contain certain threshold amounts of minerals, such as sulfur and magnesium, to deem it worthy of the official “onsen” status.
While onsen bathing is an undeniably ancient and venerated part of Japanese culture, the customs around it are by no means static. With origins documented as far back as Japan’s earliest recorded literature, onsen styles, practices, and accessibility have gone through several transformations during a more than thousand-year period–from private bathing spaces for emperors to post-battle recuperation spots for battered samurai warriors–before arriving at the onsen culture that we’re accustomed to today.
Onsen and Ancient Nara Period Texts
While the native Japanese macaques were enjoying natural onsen long before people crossed from mainland Asia to the Japanese archipelago, the earliest actual records of onsen bathing in Japan lie within Japan’s very first works of literature: the Kojiki (Records of Ancient Matters), published in 712 CE, and the more detailed Nihon Shoki (Chronicles of Japan), published in 720 CE. These ancient texts provide rare glimpses of some of Japan’s earliest hot spring customs.
The first of several onsen mentions in Nihon Shoki speaks of Emperor Jomei, who reigned from 629–641CE, visiting an onsen at Arima (now a part of Kobe’s northern ward). Beloved by the imperial family in this ancient era, this historic onsen remains a popular destination even today, heralded as one of the “Three Ancient Springs of Japan”, or nihon sankoto.
The ancient book goes on to describe onsen visits by other emperors, Empress Saimei and Emperor Tenmu, including one passage describing several messengers having been sent to now Nagano Prefecture to prepare a temporary palace for Tenmu. According to the Nihon Shoki, “The intention probably was that the Emperor should visit the hot springs of [the nearby] Tasukama,” showing the imperial precedence of soaking in these volcanic waters.
After a time-consuming, two-decade period of compilation, the Fudoki, a government record of the geography, culture, and folklore of Japan's then-provinces, was finally completed in the 730s, offering a broader perspective on how onsens were utilized by citizens all across Japan. This Nara Period administrative and anthropological book describes various onsen throughout Japan, often detailing their therapeutic qualities. One passage about a riverbank onsen in present-day Shimane Prefecture speaks to the festive atmosphere that surrounded some onsens of the time, including markets reminiscent of today’s souvenir shops, or miyageya, found at contemporary onsen resorts.
While Emperors and other upper-crust members of Nara period society would travel to onsen, common Japanese people typically could only frequent regional or local hot springs. Nevertheless, the Fudoki and subsequent book publications like the latter 8th century’s Manyoshu collection of waka poetry describe many onsen destinations, often detailing the particular medicinal and therapeutic properties of the waters, revealing the beginnings of an onsen-focused travel culture.
Early Ryokan and Onsen as Travel Destinations
It was also shortly before and during the Nara era that ryokan, Japanese-style inns, first appeared, with communal onsen bathing facilities. Most ryokan onsen during this time were outdoors and ranged from completely undeveloped natural springs to the hardscaped enclosures that are typical of today.
During the Heian period (794-1185) and beyond, onsen ryokan destinations continued to develop, often along pilgrimage routes connecting Shinto shrines and Buddhist temples which attracted the relatively small percentage of the population who had the means and time to travel. For instance, several ryokan opened during this time along the Kumano Kodo, a sacred trail linking the Three Grand Shrines of Kumano along the Kii Peninsula (what is now Wakayama, Nara, and Mie Prefectures), as well as many smaller Shinto shrines and Buddhist temples.
One such onsen ryokan destination that still thrives today is Wakayama Prefecture’s Yunomine Onsen which lies ahead of the Kumano Hongu Taisha Shrine on the Kumano Kodo. Located in a steep valley along a river with multiple hot spring vents, the onsen’s original name of yunomune, literally meaning hot water chest, is said to have come from onsen spring water bursting from a hole in the chest of the healing Buddha Yakushi Nyorai’s statue in the local temple of Tokoji, which is still there today.
Yunomine Onsen is mentioned in journals of aristocrats of the time who described their pilgrimages there, including Fujiwara Munetade, the high-ranking Minister of the Right of the imperial court during the late Heian period. It was also during the Heian period that the samurai warrior class’ use of onsen grew, coinciding with their increasing power. In the early Kamakura period (1185-1333), as samurai under the Kamakura shogunate became the dominant de facto governing force in Japan, their use of onsen often focused on therapeutics as much as spirituality, a foreshadowing of the samurai class’ prolific onsen use during the later Muromachi period.
Purification, Samurai, and Toji Onsen Therapy
The spiritual significance of onsen reached its height in the early Muromachi period (1336-1573) when the practice of yugori, or purification by onsen water ahead of visiting a shrine, became widespread among onsen visitors. The patronage of those traveling to onsen destinations also widened during this time to include well-to-do commoners, such as merchants.
Concurrently, Buddhist priests began keeping records of toji, a type of onsen therapy characterized by extended stays of two to three weeks at hot spring sites called tojiba. These records steadily advanced in sophistication as through observance, the priests refined their recommendations for best toji practices. The first handbook of toji practices is believed to have been published in the mid-Muromachi period by none other than Arima Onsen, where the Nihon Shoki recorded Emperor Jomei visiting during the 7th Century. Such handbooks, which became known as yubumi, were soon widely published across the country.
While yubumi focused on toji practices, which were rooted in spiritualism and preserved and updated by religious figures, the interest they attracted towards onsen bathing’s therapeutic benefits began to erode the religious association of onsen use. While the spiritual significance of onsen has never disappeared, as evidenced by many pilgrims today continuing to purify themselves ahead of visiting shrines, the Muromachi period can be seen as a turning point when the focus of onsen patrons became more attuned to health and leisure than to religion.
During the later Muromachi era, or Warring States period, feudal warlords, samurai, and other warriors took to visiting onsen to heal their battle injuries. Some warlords of this period kept exclusive, secret onsen, called kakushi yu, for their clans as recuperation spots. Such prudence was necessary to prevent being ambushed by their rivals while in a defenseless, bathing position. Several of these onsen live on today as public resorts touting their shrouded pasts.
When peace settled upon Japan following the Warring States period and into the early Edo era, toji onsen therapy and stays at tojiba grew in popularity as traveling became much safer. Although an ancient custom that had been around since the Nara period, toji could now be enjoyed by a much wider swath of society, including farmers and fishermen who would use the practice to recuperate during their off-seasons.
Unlike many onsen resorts, tojiba then and now are often simple accommodations, with guests preparing their own food, often via a cooking device that uses the onsen’s steam heat called a jigokugama (literally, “Hell's Cauldron”). Contemporary tojiba stays, however, focus more on relieving mental stresses than physical maladies, often going hand-in-hand with a “digital detox” break from mobile phones and laptops. The proliferation of toji during the early Edo period foreshadowed other cultural changes that would take place as the era progressed, bringing onsen culture close to what we recognize today.
The Edo Period and the Emergence of Modern Onsen Culture
During the peaceful Edo period (1600-1867 CE), Japan saw rapid urban growth and developed a wide consumer culture across several classes of society. The swelling cities produced what became known as ukiyo (meaning floating, transient world) culture characterized by the pursuit of pleasure. Ukiyo-e style woodblock prints often depicted onsen destinations, sometimes having been commissioned by particular resorts, reinforcing their appeal among ukiyo society in a sort of feedback loop. It was during the latter half of the Edo period that onsen culture in Japan took on the basic form that it has today. Onsen resorts and ryokan became destinations unto themselves for leisure and socialization, with brightly-colored brochures luring would-be vacationers by advertising fixed menus with seasonal and local delicacies, and offering package deals, no different than in modern times.
Also like now, established onsen during the late Edo period advertised their own long histories and gave bathing etiquette tips. A 1749 guidebook for the previously-mentioned Arima Onsen (the first onsen noted in Nihon Shoki) includes the onsen’s origin story, how to properly bathe, and explains the resort's special omiyage souvenirs. These guidebooks and brochures also detailed area attractions and adjacent historic sites, enticing travelers who wanted to have a well-rounded holiday. Despite the similarities to today, however, there were still some crucial differences to late Edo onsen culture that weren’t modernized until the following Meiji period, when Japan opened to the West and experienced rapid technological development.
The Meiji Period to Today: Western Influences and Advances in Technology
Although the modern concept of onsen mostly congealed during the Edo period, one crucial difference was that onsen sites were not divided by sex. From ukiyo-e depictions, it appears that onsen guests often self-segregated but mixed bathing was normal. The Meiji period (1868-1910) saw the official separation of onsen by sex as one of many efforts to Westernize Japan.
Another crucial way onsen modernized in the Meiji period was more tied to drilling technology than shifting cultural values. Kazusa-bori, a new drilling technology requiring minimal manpower, was developed in Chiba Prefecture in the late 1880s. For the first time, onsen bathing could be developed in places without natural hot springs vents. This increased upon the introduction of Western machine boring technology around the turn of the 19th to 20th centuries. Despite all this development, it wasn’t until after the Second World War in the Showa era (1926-1989) that the government of Japan officially defined what an onsen was through the onsen ho, or Japanese Hot Springs Act of 1948, which in addition to stipulating temperature and mineral requirements, also clarified issues around land ownership and how to properly inform guests of water qualities.
Following the legal definition of onsen, Western influences began to change what Japanese and foreign guests alike came to expect from onsen resorts. Sauna facilities, for instance, are a ubiquitous feature in today’s onsen but the first one in Japan, located in a public bathing facility (not a natural onsen) in Ginza, Tokyo, didn’t open till 1957. Saunas were further popularized during the 1964 Tokyo Olympics but remained mostly used by men and not part of most onsen facilities till the 1980s “Onsen boom”. The bubble economy of the time led to increased travel and consumerism and onsen resorts hurried to create lavish soaking facilities with many Western amenities.
While the opulence of the late 1980s onsens has faded, onsen culture remains an integral and distinct part of Japan that attracts significant attention and patronage from visitors from across the world. Just like the Edo period guidebooks listing local attractions, today’s onsen resorts often work with local companies to create sightseeing maps and sometimes exclusive tours of area destinations, including spots of modern interest like craft beer breweries, cross-country skiing routes, and mountain biking trails.
Onsen natural hot springs are almost as old as Japan itself, formed shortly after the first islands of Japan’s volcanic archipelago rose out of the sea and rains seeped into the land and encountered the geothermal activity just below the surface. The culture around onsen has shifted from informal cleansing among the masses concurrent with the ritualistic bathing of Nara period emperors to a gradually expanding patronage around renowned onsen destinations with particular qualities and customs. While different aspects of the onsen experience, like spirituality, medicinal use, or leisure have risen and fallen in significance over more than 1,000 years, all of these forms of onsen use are still available in modern Japan. As patrons immerse themselves neck-deep in the embrace of the waters heated by the volcanic activity hidden just below the surface, they can feel for themselves the warmth of an ancient custom that has not just evolved, but endured.
About the Author: Thomas Shomaker is an American journalist and documentary film producer. His reporting from and articles about Japan have appeared in Nikkei Asia, the energy trade publication Japan NRG, Powderlife Magazine and Wine Enthusiast. He has also worked with Tokyo’s Aoyama Gakuin University’s Digital Media Department producing Japanese and English video stories about their archiving efforts in collaboration with Washington D.C.’s Folger Shakespeare Library. A short documentary Thomas produced about Japan’s Obon Festival was recently part of a global Buddhism exhibit at the Übersee Museum in Bremen, Germany. He lives with his wife and their two children in Kansai’s Wakayama Prefecture.
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