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Medical disclaimer: This article is for informational purposes only and is not medical advice. Not medical advice. Hot-spring bathing at therapeutic temperatures is contraindicated for certain medical conditions, including uncontrolled hypertension, cardiovascular disease, and pregnancy. Consult a qualified healthcare professional before planning a wellness-focused stay if you have cardiovascular, dermatological, or other relevant health conditions.

TL;DR

• Dogo Onsen’s claim to “oldest hot spring in Japan” rests on named documentary records from the 8th century CE — the Nihon Shoki (720 CE) and Man’yōshū (approximately 759 CE) together provide the earliest surviving textual reference to a named Japanese hot spring. The claim is about documented history, not geological precedence or unbroken archaeological continuity.
• Hayao Miyazaki has publicly stated that the Aburaya bathhouse in Spirited Away (2001) was not modeled on any single real building. The Dogo Honkan’s architectural parallels are visually genuine and immediate; whether Miyazaki referenced Dogo specifically is publicly unresolved, but the connection drives significant international visitor interest regardless.
• Masaoka Shiki (正岡子規, 1867–1902), the Matsuyama-born poet who reformed modern haiku, bathed at Dogo during recuperation from tuberculosis in 1889 and 1895. The visits were explicitly recuperative — documented use of the bath as rest during illness, a structurally different frame from wellness enhancement.
• Dogo’s sodium bicarbonate spring (炭酸水素塩泉) carries a skin-smoothing association in Japanese balneotherapy literature that is physiologically plausible at the mechanism level. Controlled human outcome studies establishing durable skin effects from tourist-length bathing are limited; the claim runs ahead of what published evidence supports.

Japan’s oldest documented hot spring: what the historical record shows

The “oldest hot spring” claim requires careful reading. Japan has extensive geothermal activity across its volcanic geology; hot springs have been used for bathing throughout the country for millennia. What Dogo holds is something more specific: the oldest named literary documentation of a hot spring site in the surviving historical record.

Two foundational texts establish this position. The Nihon Shoki (日本書紀), compiled in 720 CE and one of Japan’s two oldest official chronicles, records multiple imperial visits to hot springs in Iyo Province (伊予国, present-day Ehime Prefecture). Emperor Jomei’s (舒明天皇) visit in 631 CE is among the specifically dated entries. The Man’yōshū (万葉集), compiled approximately 759 CE and Japan’s oldest surviving poetry anthology, includes poems associated with an imperial passage through the Iyo coastal region — a poem attributed to Empress Jitō (持統天皇, reigned 686–697 CE) references the harbor at Nikinatatsu, a location that Japanese scholarly tradition associates with the approach to the hot springs at Dogo.

A further layer in the historical record involves Prince Shōtoku (聖徳太子, 574–622 CE), whose traditional biography includes a healing visit to Dogo to treat illness. This tradition predates even the chronicle entries and depends on later transmitted sources rather than contemporaneous documentation; its historical grounding is less certain than the Nihon Shoki records. It appears in Dogo’s own historical materials and in Japanese cultural memory as the foundation of the bath’s therapeutic reputation — reflecting how the site has been understood for centuries: a place where sick people came with a specific purpose.

None of these records establish unbroken site continuity in the archaeological sense. The current 1894 Honkan building is not physically continuous with any earlier structure on the site. What the documentation establishes is continuous named reference to a particular Iyo Province hot spring in high-status historical sources across more than thirteen centuries — which is what “oldest” means in the Japanese documented onsen record.

The Spirited Away connection

Sen to Chihiro no Kamikakushi (千と千尋の神隠し, internationally released as Spirited Away, 2001) features the Aburaya — a multi-story wooden bathhouse serving spirits and supernatural visitors in an otherworldly setting. The building in the film is tall, lit from within at night, organized around bathing as its central function, with elaborate social hierarchies running throughout its floors.

Hayao Miyazaki’s publicly available position is that the Aburaya was not based on any single real structure. The film’s architectural vocabulary draws on a range of Japanese building traditions — Edo-period merchant townhouses, Showa-era resort hotel forms, older bathhouse structures — without a single identified source building.

The visual parallel between the Honkan and the Aburaya is difficult to dismiss on a purely perceptual basis. Both are multi-story wooden public baths from an earlier century. Both carry layered eaves, decorative roof elements, and the visual complexity that large wooden Japanese buildings in the late Meiji period produce. The Honkan at night — windows lit, steam visible, the shachihoko (鯱, ceramic fish-shaped roof ornaments) silhouetted against the sky — places a viewer in a visual relationship with the film’s nighttime exterior shots that does not feel incidental.

What is documented without ambiguity: Spirited Away remains Japan’s highest-grossing domestically produced film, and the Dogo–Spirited Away association circulates widely in international travel coverage and in social media documentation of the destination. It is among the most frequently cited motivations for international visitors to include Dogo in a Shikoku itinerary. Matsuyama’s tourism materials acknowledge the association while noting Miyazaki’s stated position. Both facts exist simultaneously.

For visitors oriented toward this angle, The Art of Spirited Away documents the visual development process and the reference sources Miyazaki and Studio Ghibli drew on in producing the film’s built environment.

Masaoka Shiki at Dogo: recuperation and the literary record

Masaoka Shiki (正岡子規, 1867–1902) was born in Matsuyama and left the city at sixteen to pursue a literary career in Tokyo. He returned to his home prefecture in 1889 after coughing blood on a train — a visible early symptom of the pulmonary tuberculosis that would accelerate across the following thirteen years and kill him at thirty-four.

During his 1889 recuperation in Matsuyama, Shiki bathed at Dogo and began the systematic critical and creative work that would reshape haiku as a literary form. He returned again in 1895, the same year Natsume Sōseki arrived in Matsuyama as an English teacher. The two were acquaintances from Tokyo literary circles; their overlapping period in Matsuyama is documented in both writers’ correspondence and biographies.

The texture of Shiki’s relationship to Dogo differs from the frame that Sōseki’s novel Botchan (坊っちゃん, 1906) supplies. In Botchan, the bath functions as a reliable minor pleasure for an irritable young man posted somewhere he doesn’t want to be — a small, repeatable comfort. For Shiki, the bath was part of a documented illness management routine during active disease. He visited while sick, aware of his limited energy, and his writing from these Matsuyama periods reflects both creative intensity and physical constraint. The bath offered rest and warmth in a familiar location during a phase of real illness. That is a different frame from wellness enhancement: it is the historical use of the bath as recuperative space for a specific person managing a specific condition.

This distinction matters for reading the wellness-travel category honestly. The tradition of therapeutic bathing at Dogo — documented from the Shōtoku tradition through the Nihon Shoki imperial visits through Shiki’s recuperative sessions — is a record of the bath as a place sick people came to rest, not as a longevity enhancement destination in the modern sense. The framing is worth holding accurately.

Masaoka Shiki haiku collections in English translation are the most direct access to his work. The Shiki Memorial Museum (子規記念博物館) in Matsuyama provides physical context for his life in the city and is a natural complement to an afternoon anchored at Dogo.

Sodium bicarbonate springs: chemistry and calibration

Dogo’s spring is classified as 炭酸水素塩泉 (sodium bicarbonate / bicarbonate spring) under Japan’s Ministry of the Environment 温泉法 framework, with a mildly alkaline pH at bathing temperature and a source temperature of approximately 42°C.

The skin-smoothing association this spring type carries in Japanese balneotherapy literature — often described in promotional contexts as 美肌の湯 (bihada no yu, skin-smoothing water) or 美人の湯 (bijin no yu) — has a physiologically plausible proposed mechanism: mildly alkaline water at bathing temperature may soften the outer keratin layer of the skin surface, producing a perceptible smoothness during and immediately after immersion. This effect is physiologically coherent. What is not established by controlled human outcome studies is whether a standard tourist bathing session at Dogo produces durable changes to skin barrier function beyond the immediate perceptible texture change during and after the bath.

The broader thermal bathing evidence base — covered in detail in The Onsen Effect and in the Dogo Onsen spring chemistry overview — involves cohort data (Ueda et al. 2018, Heart, approximately 38,000 Japanese adults followed 19 years) documenting associations between habitual daily thermal bathing and cardiovascular markers. That research does not differentiate by spring mineral type; the associations appear linked to bathing temperature and long-term daily frequency, not to bicarbonate chemistry specifically. A single visit to Dogo, regardless of spring type, is not the exposure pattern that cohort data describes.

The calibration required for this category: at-home sodium bicarbonate mineral additives or a tourist visit to the Honkan are a different exposure context from the long-term supervised bathing protocols that clinical balneotherapy literature examines. A trip to Dogo is not a medical treatment or preventive health protocol. Japanese sodium bicarbonate onsen bath additives carry the mineral component; they do not replicate the maintained source temperature, the 1894 building, or the session format of the original context.

The Reiwa renovation and the three-facility circuit

The Honkan’s Reiwa-period renovation (2019–2024) addressed structural and systems maintenance while keeping the building in active use — a demanding circumstance for a structure carrying Important Cultural Property designation. Buildings in that category typically operate under strict use restrictions; the Honkan’s continued functioning as a public bathhouse throughout phased structural work is a distinctive position within the designation. Portions of the building were closed in rotation as work proceeded and have been reopened progressively. Confirming current access conditions via the official Dogo Onsen operating authority before visiting is practical.

The Dogo district operates two additional facilities drawing from the same spring sources:

Asuka-no-yu (飛鳥乃湯泉): A 2017-built facility adjacent to the Honkan, designed in an aesthetic referencing the Asuka-period history associated with the Shōtoku tradition. Offers private resting rooms (個室) that the Honkan’s tiered entry structure does not. Has hosted rotating art installations under the Dogo Art project. For visitors for whom communal bathing is impractical, private room access here is the standard alternative.

Tsubaki-no-yu (椿の湯): The local-use facility, priced lower than the Honkan and oriented primarily toward Matsuyama residents. A practical option for a second or third session during a multi-day stay when the Honkan queues are long, or when a quieter bath environment with less visitor concentration is the priority.

Imabari Towel: Ehime Prefecture is Japan’s dominant towel production region. Imabari (今治), approximately 50 kilometers north of Matsuyama, holds the only nationally recognized towel fabric quality certification in Japan (今治タオルブランド認定), covering cotton composition, absorbency, and dye standards. Imabari-certified towels appear throughout the Dogo arcade souvenir shops as the standard textile purchase from the district — the connection is regional production context rather than tourism-invented branding. Imabari-certified Japanese cotton towels are available internationally for those who want the textile without the trip.

Practical matters

Access: Matsuyama Airport receives direct flights from Tokyo Haneda (approximately 1 hour), Osaka Itami, and Fukuoka. From Shin-Osaka by rail via Okayama and the Seto Ohashi Bridge, total travel time runs approximately 3 to 3.5 hours. The Matsuyama City Tram (道後線, Dōgo-sen) connects JR Matsuyama Station to the Dogo Onsen terminal in approximately 15–20 minutes.

Timing: The Honkan opens at 6am on standard operating days. Early morning bathing substantially reduces queuing relative to the peak period concentrated between 11am and 6pm on weekends and Japanese public holidays. Evening bathing — after the main visitor volume has cleared — produces the lit-building exterior conditions most associated with the Spirited Away visual comparison and with nighttime photography of the destination.

Accommodation and tours: English-language ryokan and inn inventory within walking distance of the Honkan is available through Booking.com. Day tour packages from Osaka, Hiroshima, and Okayama combining Matsuyama Castle and Dogo Onsen are available through Klook. The Shikoku travel and Dogo Onsen guidebooks available at the arcade bookshops and internationally provide trip planning context that covers the 88-temple Henro pilgrimage circuit alongside the Matsuyama itinerary.

Cardiovascular cautions: Standard thermal bathing cautions apply: uncontrolled hypertension, active cardiovascular disease, and pregnancy are primary contraindications, driven by water temperature (40–42°C) rather than by bicarbonate chemistry specifically. Discuss bathing parameters with a physician before visiting if any of these conditions apply.

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Part of the wellness travel series. See also: Dogo Onsen: 1894 Honkan Architecture and Spring Chemistry, The Onsen Effect: Cardiovascular Research, Onsen and Blood Pressure: Cohort and RCT Evidence, Japanese Onsen Ryokan: How to Choose and Book, Beppu Hatto: Eight Springs and the Toji Tradition, Nyuto Onsenkyo: Seven Springs and Secluded Bathing, Kusatsu Onsen: Acid Sulfur Spring and Balneotherapy Research, Shikoku Henro Pilgrimage and Wellness Walking.