Scenes of people enjoying sento are common in Japanese movies, anime, and manga, highlighting this unique cultural aspect. In Tokyo, there are over 430 sento, always bustling with visitors.

So, why do Japanese people love sento so much? It's because sento offer unique experiences and enjoyment that you can't get from a home bath. This article will share why we Tokyo locals love sento and why they’re a hidden gem for foreign visitors to discover.

The history of public baths is ancient and fascinating. Large public bathhouses have been discovered in the ruins of the Indus Valley civilization’s Mohenjo-Daro (circa 5000 years ago), Mesopotamia (around 4000 BCE), and ancient Greece (circa 2000 BCE). These findings indicate that humans have long enjoyed bathing for both hygiene and religious reasons.

In particular, the Roman Empire around 100 BCE developed luxurious public baths known as thermae, which had functions similar to modern Japanese onsens and sento.

In Japan, the history of sento began after the introduction of Buddhism in the 6th century. Buddhism encouraged cleanliness, leading to the construction of bathhouses in temples. These bathhouses were eventually opened to local residents, marking the beginning of Japan's sento tradition.

Japanese people are known for their love of baths, a passion that can be traced back to Japan's unique geographical features.

First, Japan is dotted with volcanoes, resulting in over 3,000 hot springs across the country. Evidence of hot spring usage dates back thousands of years to the Jomon period.

Additionally, Japan sees plentiful precipitation. The abundant rainfall and snowmelt provide ample water for Japanese people to collect water for baths.

In the summer, Japan experiences high temperatures and humidity due to the hot and humid Ogasawara air mass from the Philippines. This makes sweating uncomfortable and unhygienic, prompting people to bathe frequently to stay clean and comfortable.

Conversely, Japanese winters are cold and dry, influenced by Siberian air masses that pick up moisture over the Sea of Japan, causing heavy snowfall on the western side and cold, dry air on the eastern side. This climate necessitated regular bathing historically, to wash away dust and dirt, and to warm up during the colder months.

Even 400 years ago, when Tokyo was known as Edo, cold, dry winds would stir up dust, making baths essential for cleanliness and warmth. This historical necessity has evolved into a cultural preference that continues to this day

While cool water baths are fine in Japan's hot, humid summers, winter presents a different challenge. In modern Tokyo, January temperatures average 10°C (50°F) during the day and drop to 2°C (36°F) at night, with occasional snowfall. Such cold weather requires hot baths.

Japanese houses, both now and in the Edo period over 400 years ago, are mostly made of wood. Today, around 85% of homes are wooden, and in Edo times, nearly all buildings were wooden. The biggest issue with wooden houses is the risk of fire, especially in the dry winter air. To reduce fire hazards, instead of heating water at home, many residents paid to use public bathhouses, or sento, which became common in Edo.

In Edo, about 20% of the population were daimyo and samurai, who occupied 80% of the land. The remaining 80% of the population, the townspeople, lived in the remaining 20% of the area, creating a densely packed living environment. By the early 18th century, Edo's population had grown to over a million. Most homes lacked space for personal baths, and the cost of wood for heating water was too high for individual households. Sento, with their affordable hot water, became widely popular.

It's said that during the Edo period, there was a sento in every ward. These bathhouses also served as social hubs where people could relax after their baths, enjoy tea and snacks, and play games like Go or Shogi, fostering a sense of community among the residents.

In 1923, the Great Kanto Earthquake struck Tokyo at noon, causing widespread fires as people were cooking lunch. With the densely packed wooden houses, over 60% of the city's buildings were destroyed, including many sento.

To rebuild the destroyed sento, shrine carpenters known as "miyadaiku" played a crucial role. They used their skills to create more luxurious buildings, incorporating the grand architectural style of Japanese shrines.

They used tiles, which had recently been introduced from the West, to adorn the bathhouses and installed large bathtubs. High ceilings were designed to prevent steam buildup, and the walls were painted with expansive murals of natural scenes like the ocean, lakes, Mount Fuji, and the sky, creating an immersive and majestic atmosphere.

People visiting these sento were captivated by the grandeur of the architecture, the spacious interiors, and the stunning murals, offering an escape from their everyday lives.

In the 1950s, a new tradition emerged at sento: drinking milk after a bath. Milk was highly nutritious but required refrigeration, which most households didn't have at the time. To promote milk consumption, manufacturers installed refrigerators at sento and sold milk there. This practice became a beloved part of the sento experience and remains a unique aspect of Japanese culture today.

In the 1950s, only a few homes in Japan had bathrooms, so most people relied on public baths, or sento. By 1963, over 60% of households had their own baths, allowing more people to enjoy bathing at home. However, for Japanese people, bathing has always meant soaking in a tub, not just taking a shower. As a result, over 95% of Japanese homes today have bathtubs in addition to showers.

In Western countries, bathtubs are typically used by individuals for washing both hair and body. In contrast, for Japanese people, bathing has traditionally involved going to a sento, where the tub is a shared space. This communal aspect led to the development of specific bathing etiquette to keep the shared bathwater clean.

Before entering the communal bath at a sento, individuals thoroughly wash their hair and body. This ensures that everyone enters the tub clean. Additionally, it is customary not to bring towels or wear undergarments in the bath. At sento, there are designated washing stations equipped with showers and stools, where people clean themselves before soaking in the large shared tub.

When exiting the bath, it is polite to towel off excess water before returning to the changing area. This practice helps keep the floor dry and comfortable for other users. These customs reflect the importance of consideration and respect for others in Japanese bathing culture, whether at a sento or at home.

Even though most households in Tokyo have their own bathtubs, many people still pay to frequent sento. This is because public bathhouses offer experiences unlike any you could have at home.

The warm water helps to relax the body, reduce stress, and relieve fatigue by promoting blood circulation and loosening muscles and joints. The water pressure in the bath also helps to improve blood and lymphatic flow, aiding in the removal of fatigue-inducing substances and waste from the body.

Sento baths are much larger than those at home, allowing for a more comfortable and relaxing experience. Scientific studies show that the brain produces three to six times more alpha waves, which are associated with relaxation, in large baths compared to small home bathtubs. Additionally, the large amount of water in the sento generates negative ions, similar to those found near waterfalls, which further enhance relaxation.

Sento also have high ceilings to prevent steam buildup, creating an open and airy feeling that adds to the sense of relaxation. Many sento feature murals of majestic natural scenes, such as Mount Fuji and the ocean, which enhance the relaxing atmosphere.

Sento baths are also deeper and wider than home baths, providing stronger water pressure and a higher degree of relaxation and fatigue recovery. Furthermore, sento often offer a variety of bath types, such as bubble baths, ultrasonic baths, cascading baths, lying-down baths, electric baths, carbonated baths, medicinal baths, and open-air baths. Many sento in Tokyo even use natural hot spring water.

These facilities and features are rarely found in home baths, making sento a unique and valuable experience. Recently, the addition of saunas has become particularly popular, drawing even more people to sento.

Another important reason people continue to visit sento is their role as community hubs. Whether after work or sports, people in the neighborhood come together to bathe and relax, strengthening their bonds. This experience is known in Japan as "naked communion," highlighting the sense of camaraderie and connection that comes from shared bathing experiences.

At sento, it's common to exchange polite greetings with others, showing respect for the shared space and experience. This fosters a sense of community, with regulars often helping newcomers and engaging in friendly conversations. It's not unusual to hear exchanges like:
- "Do you live nearby?"
- "Where are you visiting from?"
- "Good work today."
These kinds of friendly conversations can be heard all the time at sento.

Sento are the best-kept secrets of Tokyo that locals adore.

With an admission fee of only 550 yen for adults (as of August 1, 2024), there may be no better way to experience Tokyo.

Enjoy a truly local experience by stopping by one of Tokyo's many sento!