Many Japanese hot springs and sento are designed with separate changing rooms, washing areas, and baths for men and women. To visitors to Japan, this may seem natural, but looking back through history, it was not always this way.

In short, gender separation became the standard because mixed bathing was regulated during Japan's Meiji-era modernization. Until the Edo period, mixed bathing was not unusual, but the Meiji government, strongly conscious of the West, began cracking down on it from the standpoint of public morality. Later, changes in privacy awareness and the systematization of rules through the Public Bath Law and local ordinances helped establish the current norm of gender-separate bathing.

This article focuses specifically on one question: why did gender separation become the mainstream? The reason Japanese hot springs are used nude is covered in Why Are Japanese Hot Springs Used Nude?, while the history of mixed bathing itself and the few places where it still survives are explained in What Is a Mixed-Bathing Hot Spring? History and Why It Still Remains and How to Enter a Mixed-Bathing Hot Spring. Here, we will focus only on how bathing became gender-separated.

Mixed bathing was once common in Japan

To understand why gender separation took hold, it is important first to note that Japan was not originally gender-separate. Until the Edo period, mixed bathing was commonly seen in sento and hot spring resorts in many regions. In an era when most homes did not have baths, bathhouses were shared community infrastructure, and bathing was primarily about cleanliness and warming the body.

In other words, gender separation was not an age-old, naturally Japanese form. It was a form that society chose at a certain point in history. So when, and why, did that turning point arrive?

The turning point was Meiji modernization and the Western gaze

Mixed bathing changed dramatically in the Meiji era. Seeking to stand alongside the Western powers, the Meiji government began reassessing everyday customs through a new standard of whether they were civilized. Within that context, mixed bathing came to be seen as a custom that should be corrected under Western moral values.

In fact, records left by foreign visitors to Japan before and after the opening of the country often show a moral objection to mixed bathing. For Westerners who came to Japan, men and women bathing together was hard to understand, and this awareness of an outside gaze is said to have been one of the motives for a government trying to present itself as a modern nation. The ban on mixed bathing was driven less by sanitation policy alone and more by concerns over external respectability and public morals.

The regulatory steps that cracked down on mixed bathing

The transition unfolded gradually through several regulations.

In 1872, Tokyo Prefecture issued the Ishiki Kaii Ordinance, which prohibited mixed bathing while also cracking down on minor offenses and imposing penalties on violators. Along with public urination and going out naked, mixed bathing in bathhouses was made a target of enforcement. The following year, this ordinance was extended to other regions, spreading the regulation nationwide.

Then in 1900, an order from the Ministry of Home Affairs effectively prohibited mixed bathing in public bathhouses nationwide, with an exception for children under 12. This made gender-separate bathhouses common in urban areas, and the practice spread across the country. However, the rules did not take root overnight. Mixed bathing did not decline significantly until the late Meiji period, and it remained in some rural hot spring areas for a long time. It took considerable time for the form required by law and the reality of bathhouses to fully align.

After the war, it was institutionalized through law and local ordinances

After becoming the norm in the Meiji era, gender separation was further established as a system within the legal framework after World War II.

The Public Bath Law was enacted in 1948. This law required permission from the prefectural governor to operate a public bath and placed certain obligations on both operators and users from the standpoint of public health and morals. The key point is that specific hygiene standards such as ventilation, lighting, and cleanliness, as well as restrictions on mixed bathing between men and women, were left not to the law itself but to ordinances set by each local government.

As a result, the practical age thresholds for restricting mixed bathing are also set by each prefecture and other local authorities in reference to national guidance. The gender-separate form is supported not only by cultural habit, but also by this framework of law and local ordinances. Practical age standards for bathing with children are discussed in How to Enter a Mixed-Bathing Hot Spring.

Changes in privacy awareness also reinforced gender separation

Not only legal systems, but also changes in public consciousness helped gender separation take root. From the modern era onward, attitudes toward nudity and personal space changed greatly from the Edo period, and resistance to sharing a bath naked with an unfamiliar person of the opposite sex became widespread.

As home baths became more common and bathing turned into a private activity, and as values that respected privacy spread, it became natural to assume that gender separation in public baths meant peace of mind. The fact that many modern hot spring inns and day-use facilities are designed from the outset with gender separation in mind is closely tied to this shift in awareness. In other words, gender separation became established through both top-down regulation and bottom-up changes in user attitudes.

Today, gender separation is the standard

Through this historical process, gender separation is now the norm in Japan. Most large baths in traditional hot spring inns, communal bathhouses, and sento are designed on the assumption that men and women bathe separately. It is true that mixed bathing still exists, but only at a very limited number of facilities and in a few regions; it is not a common option.

For first-time visitors to Japanese hot springs, it is best to assume gender separation first to avoid confusion. If families or couples want to bathe together, private baths, family baths, or in-room baths are the practical choice. While maintaining gender separation as the default, Japanese hot springs commonly provide another way to enjoy bathing together. For basic bathing etiquette, please refer to Hot Spring Etiquette Guide.

FAQ

Why are Japanese hot springs gender-separate?

The starting point was the regulation of mixed bathing during Meiji-era modernization. The Ishiki Kaii Ordinance of 1872 and the Ministry of Home Affairs order of 1900 banned mixed bathing, and later changes in privacy awareness plus institutionalization through the Public Bath Law and local ordinances established gender separation as the standard.

Were Japanese hot springs always gender-separate?

No. Until the Edo period, mixed bathing was not unusual in sento and hot spring areas. Gender separation became common only after the Meiji era.

Why was mixed bathing banned in the Meiji era?

Because the Meiji government, strongly aware of the West, viewed mixed bathing as a custom that should be corrected from the standpoint of public morals. The fact that foreign visitors to Japan also regarded mixed bathing as problematic is said to have reinforced the government's concern for international respectability.

Does mixed bathing still exist now?

It remains at a very limited number of facilities and in certain regions. However, in modern Japan, gender separation is the rule, and mixed bathing is not a common option. For more details, see What Is a Mixed-Bathing Hot Spring? History and Why It Still Remains.

What should families or couples do if they want to bathe together?

Using a private bath, family bath, or in-room bath is the practical option. The common approach is to keep gender separation as the default while bathing together in a private space.

Summary

Japanese hot springs are gender-separate not because they have always been that way, but because mixed bathing was regulated during Meiji-era modernization. Western-conscious morality regulations, including the 1872 Ishiki Kaii Ordinance and the 1900 Ministry of Home Affairs order, made gender separation the norm, and after the war, the Public Bath Law, local ordinances, and changes in privacy awareness further solidified today's standard. Historically, there was once an era of mixed bathing, but in modern Japan it helps to know that hot springs are generally enjoyed on the assumption of gender separation.

Sources

• National Diet Library Reference Cooperative Database: What Kind of Ordinance Was the Ishiki Kaii Ordinance?
• Miki Kawabata, Considerations on the "Yuya Torishimari Kisoku" and "Yuya Eigyo Torishimari Kisoku" (Core Ethics)
• Public Bath Law (Act No. 139 of 1948, e-Gov Law Search)