Retro sento are bathhouses that strongly preserve the architecture and design of public baths from the Showa era. Their value lies not simply in being old buildings, but in retaining features exactly as they were: a shrine-like miyazukuri exterior, a karahafu entrance roof, a large Mount Fuji mural at the back of the bath, a bantsuke counter in the changing room, and tsuboniwa gardens and tile murals.

These design elements did not appear by chance. Many were shaped by urban life, advertising culture, and recovery from disaster from the Taisho through the Showa periods. In other words, reading a retro sento is almost the same as tracing the everyday life and architectural style of Showa Japan.

This article organizes the representative architectural and design elements found in retro sento, along with their origins and meanings. For the institutional differences between hot springs and sento, such as the Hot Springs Act and Public Bathhouse Act, see the difference between onsen and sento. For how to choose among the full range of Japanese bathing facilities, including sento, see types of Japanese bath facilities. This article focuses on architecture and Showa culture.

A list of retro sento architecture and design

First, here is a summary of the representative features commonly seen in retro sento, together with their origins and meanings. Regional differences are significant, and miyazukuri and Mount Fuji mural paintings are especially rooted in sento culture in the Tokyo and wider Kanto area.

Below, we will look in order at the elements with the deepest historical background.

Miyazukuri and karahafu: a style born from earthquake reconstruction

When people think of Tokyo sento, they often picture a grand structure with a large roof reminiscent of a shrine. This style, called miyazukuri, is actually not that old.

Before the Great Kanto Earthquake in 1923, Tokyo bathhouses were mostly modest machiya-style buildings, just like in other regions. After many were destroyed by fire in the earthquake, shrine carpenters used their skills during reconstruction to create more imposing bathhouses with karahafu entrances and open, coffered ceilings in the changing rooms. These bathhouses gained a strong reputation and spread, eventually making miyazukuri the standard image of a sento in Tokyo. That is why miyazukuri is a style centered in Kanto, while in other regions different architectural forms are more common.

The karahafu roof ornament above the entrance is a curved decorative roof feature that was considered the most prestigious design in the Edo period. Its use in a public bath shows the desire of the time to present the sento as something special by bringing a style once used for shrines, temples, and castles into an everyday bathing space. Karahafu is also said to symbolize an entrance to paradise. For a broader view of hot spring inn and bathhouse architecture, see Japanese onsen architecture that designs the bathing experience.

The Mount Fuji mural: a background painting born from advertising

The Mount Fuji mural rising at the back of the bath is a signature feature of retro sento. Its origin is said to be Kikai-yu in Kanda-Sarugakucho, Tokyo, in 1912. During a renovation of the bath area, a background painting was installed to delight children, and the story goes that Shiroshiro Kagoshiro, a Western-style painter from Shizuoka, painted Mount Fuji, his birthplace. Kikai-yu, the original site, closed in 1971, but a plaque marking it as the birthplace remains.

The spread of Mount Fuji murals was unexpectedly driven by advertising. Seeing the popularity of these background paintings, businesses created a system in which, instead of hanging ads below the mural, they collected advertising fees from sponsors and had the mural painted for free. Through this connection with advertising, Mount Fuji murals rapidly spread to sento across Japan. At the same time, this mural culture was mainly a Kanto-area phenomenon, and regional differences remain, with bathhouses in places such as Osaka generally not painting Mount Fuji on the wall.

Today, very few artists can still paint these murals professionally, so a surviving mural itself may be considered precious. Even among wall decorations, tile murals made from ceramic panels such as Kutani ware belong to a different cultural stream from Mount Fuji murals, with patterns and colors varying by region and era.

Bantsuke and tsuboniwa: fixtures that reflect Showa daily life

Bantsuke was a raised counter placed at the entrance to the changing room. It served to receive payment while overlooking both changing rooms and keeping watch over the bathhouse. Another hallmark of miyazukuri sento is the open coffered ceiling often found in the changing room, creating both openness and a sense of formality.

Tsuboniwa gardens, set beside the bath area or changing room, are another feature that gives retro sento their character. Some include small koi ponds, showing an effort to bring nature into a limited lot. High walls separating the men’s and women’s baths, along with decorative elements installed above them, also clearly reflect the structures of the time.

In recent years, more sento have begun using front-desk reception instead of a bantsuke counter after customers leave their shoes at the entrance. Whether a bantsuke remains is one clue to how much of the old structure a bathhouse still preserves.

The Kerorin bucket: a prop that still carries Showa advertising

Showa culture lives not only in architecture but also in small items such as bath buckets. The yellow Kerorin bucket began in 1963 as an advertising medium for the painkiller Kerorin. It was originally white, but the color was changed to yellow because stains from bath residue were said to show up too clearly. The first ones were placed in a bathing facility in Tokyo, and from there they spread nationwide.

Although the bucket itself is a consumable item, it has continued to be used in the same design for more than half a century, showing how Showa advertising culture became part of everyday life. In retro sento, each of these small objects conveys the tactile atmosphere of daily life at the time.

The shrinking sento industry and renewal as design sento

One unavoidable topic when talking about retro sento is the decline of sento itself. According to the National Federation of Public Bathhouse Business Associations, the number of sento in Japan peaked at around 18,000 in 1968 and has continued to fall as home baths spread during the high-growth period, dropping in recent years to fewer than 2,000. Losing one miyazukuri sento means losing a place where architecture, design, and local culture remain together.

At the same time, there has been a growing movement to renovate old sento into modern design sento. Architects and artists are involved, preserving the traditional atmosphere and background-painting culture while turning these spaces into places that appeal to younger generations and sauna enthusiasts. One well-known example is Kogane-yu in Kinshicho, Tokyo, where architects and artists collaborated to renovate a long-established bathhouse and attract not only local regulars but also new visitors. Retro sento are becoming not just places to preserve the past, but places where new value is created from Showa-era design.

If you want to visit one in person, start by searching by region on the facility list. For how Japanese bathing culture developed over time, see the history of Japanese bathing culture.

FAQ

When did miyazukuri bathhouses begin to be built?

They are said to have spread around Tokyo during the reconstruction period after the Great Kanto Earthquake in 1923. Before the earthquake, modest machiya-style bathhouses were the norm, but during reconstruction, shrine carpenters showed their skill and the grand style with karahafu and coffered ceilings became widespread.

Why are so many sento murals of Mount Fuji?

Their origin is said to be Kikai-yu in Kanda-Sarugakucho, Tokyo, in 1912. The mural became popular, and a system developed in which advertising was combined with the background painting, allowing it to be painted for free using sponsorship fees. However, this Mount Fuji mural culture is mainly from the Kanto area, and it is not common in places like Osaka.

What is the difference between a bantsuke and a front desk?

A bantsuke is a raised counter at the entrance to the changing room that traditionally serves both as a reception point and a place to supervise the bathhouse while overlooking both changing rooms. In recent years, more bathhouses have switched to front-desk reception, and whether a bantsuke remains is one indicator of whether an old structure is still preserved.

Why is the Kerorin bucket yellow?

When it was created in 1963 as an advertising medium for the painkiller, it was originally white, but it is said to have been changed to yellow because stains from bath residue showed too clearly. It continued to be used in the same design for more than half a century and became a symbol of Showa-era sento.

Are retro sento still increasing today?

Sento themselves have declined sharply from their peak in 1968, and new miyazukuri bathhouses are almost never built today. On the other hand, there is a growing movement to revive old bathhouses as modern design sento in various places.

Conclusion

Features preserved in retro sento—miyazukuri, karahafu, Mount Fuji mural paintings, bantsuke counters, tsuboniwa gardens, tile murals, and Kerorin buckets—were all born from the urban life, advertising culture, and earthquake reconstruction of the Taisho and Showa periods. Miyazukuri spread after the Great Kanto Earthquake, and the Mount Fuji mural began at Kikai-yu in 1912 and spread together with advertising. Knowing this background makes it clear that a single bathhouse can convey the whole texture of everyday life at the time. As sento continue to decline, new efforts are emerging to revive them as design sento. Retro sento are a rare gateway into the architecture and culture of Showa Japan.

Sources

• nippon.com, "The beginnings of sento—the bathing culture of ordinary people"
• Nikkei, "Why is there a Mount Fuji mural in sento? The driving force was an unexpected advertising business model"
• Tokyo Shoko Research, "Neighborhood sento: 16,000 fewer than at peak"
• Kerorin bucket - Wikipedia