When you look up, the universe is there.

Countless stars spread across the sky above. The Milky Way is clearly visible. Shooting stars leave a trail of light before disappearing. It might be the first time in your life you've seen so many stars.

I found myself unable to move, soaking in the open-air bath. The warmth of the hot spring and the beauty of the starry sky were a combination too perfect to resist.

Starlit onsen is an experience that makes you aware of being part of the universe. It allows you to feel both how small you are and yet, at the same time, that you are a part of this vast universe. It's a mystical time that lets you experience both.

The True Starry Sky Only Seen in Light-Pollution-Free Areas

Living in urban areas, opportunities to see the starry sky are rare. The city lights are too bright, and stars are only faintly visible. At best, you might see a few bright first-magnitude stars.

However, in the remote hot spring areas of the mountains, the situation is entirely different. Far from city lights, there is almost no light pollution. As a result, an unbelievable number of stars can be seen.

The stars visible in urban areas are just a small fraction of the whole. The true starry sky is filled with a number of stars far beyond imagination. Many people discover this fact for the first time at a starlit onsen.

The Perfect Combination of Hot Springs and Starry Skies

Why is it special to see the starry sky from a hot spring? It's because the state of relaxation and stargazing are a perfect match.

In typical stargazing, you stand or sit in a chair looking up at the sky. However, this posture can strain your neck over time, making it difficult to continue gazing at the stars.

In contrast, in an open-air bath, you can look up at the sky in a nearly supine position. Rest your head on the edge of the tub, with your body soaking in the hot spring. In this posture, there's no strain on your neck, allowing you to gaze at the stars for hours.

Moreover, the relaxation effect of the hot spring adds to the experience. A warmed body, relaxed breathing, and a calm heart rate. In this state, looking at the starry sky evokes a deeper sense of wonder. With an open heart, the beauty of the universe seeps into your soul.

Famous Starlit Onsen Locations

Japan has many wonderful starlit onsens.

Achi Village (Nagano Prefecture): Known as "the village with the most beautiful starry sky in Japan." The high altitude and low light pollution allow for a breathtaking view of the stars. You can bathe while gazing at this starry sky in the village's hot spring facilities.

Around Yatsugatake (Nagano and Yamanashi Prefectures): High altitude and clear air. At the foot of Yatsugatake, there are many hot springs. The starry sky viewed from the open-air baths is truly spectacular.

Around Lake Towada (Aomori and Akita Prefectures): Surrounded by the deep forests of northeastern Tohoku. There's almost no light pollution, and you can see a sky full of stars. In hidden hot springs like Nyuto Onsenkyo, you can have a primal starry sky experience.

Yakushima (Kagoshima Prefecture): A World Natural Heritage island. The southern starry sky shows constellations different from those on the mainland. You can even see the Southern Cross. Enjoy the southern starry sky at the island's hot spring facilities.

Iriomote Island (Okinawa Prefecture): Japan's southernmost starry sky spot. The Southern Cross is clearly visible, and the density of the Milky Way is overwhelming. The experience of being enveloped by the southern starry sky in a hot spring surrounded by jungle is unforgettable.

The Awe of Seeing the Milky Way from a Hot Spring

The most moving moment in a starlit onsen is seeing the Milky Way.

The Milky Way is almost invisible to the naked eye. In urban areas, it's completely obscured by light pollution. However, in the light-pollution-free mountains, the Milky Way is clearly visible, crossing the sky like a white band.

Soaking in an open-air bath, you look up at this Milky Way. A collection of hundreds of billions of stars. You're seeing our galaxy from the inside. Understanding this fact leaves you speechless.

The dense parts of the Milky Way look like clouds. But they're not clouds. They're clusters of stars. This realization makes you feel the vastness of the universe and understand the smallness of your existence.

The Luxury of Wishing on a Shooting Star

In a starlit onsen, the chances of seeing a shooting star are high. With no light pollution, even small shooting stars are not missed.

When a shooting star appears, you instinctively exclaim "Ah!" and quickly think of a wish. However, shooting stars disappear in an instant, often before you can finish your wish.

Still, seeing a shooting star brings happiness. Capturing a fleeting phenomenon of the universe with your own eyes. This serendipitous fortune is delightful.

The Best Time is a Moonless New Moon Night

For stargazing, a moonless night is ideal. On a full moon night, the moon is too bright, and the stars fade.

On a new moon night or after the moon has set, the starry sky is most beautiful. Without moonlight, even dim stars are visible. You can observe the details of the Milky Way.

When booking a hot spring inn, choose the time around the new moon. This planning ensures the best starlit onsen experience. Check the lunar calendar and choose a date close to the new moon. This small effort makes a big difference.

The Fantastical Combination of Starry Skies and Steam

Winter starlit onsens have a special beauty. It's the combination with steam.

On cold winter nights, a lot of steam rises from the hot spring. This steam softly envelops the starry sky. Stars flicker through the steam, creating a fantastical scene.

As the steam flows with the wind, stars appear and disappear. This dynamic change adds depth to stargazing. You can enjoy not only the stars but also the movement of the steam.

Viewing the starry sky through the steam feels like being in another world. Reality fades, and you feel like you're in a dream. This sense of being out of the ordinary is the charm of starlit onsens.

The Joy of Finding Constellations

In a starlit onsen, there's also the joy of finding constellations.

Orion, the Big Dipper, Cassiopeia. Even beginners can find famous constellations. Soak in the hot spring and slowly search for constellations. This intellectual play makes stargazing many times more enjoyable.

Using a smartphone constellation app makes it even more fun. Just point it at the sky, and it tells you which stars belong to which constellations. "That's Vega," "That's Antares." Knowing the names of stars deepens your familiarity with the starry sky.

However, the light from your smartphone can be a nuisance to other bathers. It's important to be considerate when using it.

What the Starry Sky Teaches Us

Watching the stars in a starlit onsen naturally leads to philosophical thoughts.

The light from the stars we see was emitted years ago. Light from stars tens or hundreds of light-years away. In other words, what we see is the past appearance of the stars.

Understanding this fact makes the concept of time and space waver. Here you are now, but what you're seeing is the distant past of the universe. This strange sensation leads the mind into a deep meditative state.

How small you are. Yet, at the same time, you are part of this grand universe. These contradictory feelings coexist. Starlit onsen is an experience that fundamentally questions human existence.

The Silence of Starlit Onsen

Starlit onsens are overwhelmingly quiet.

In the remote hot spring areas of the mountains, there are almost no artificial sounds. No car noises. No human voices. You only hear the sound of the hot spring, the chirping of insects, and the occasional sound of the wind.

Watching the starry sky in this silence enhances the quality of the experience. You can focus on your vision. You can feel the vastness of the universe without interruption.

Silence calms the mind. Breathing deepens, heart rate drops, and thoughts quiet down. In this state, simply watching the starry sky becomes meditation. Starlit onsen is not an active sightseeing experience but a static one.

Starlit Onsen is an Experience Connecting with the Universe

Starlit onsen is an experience that connects you with the universe.

Wrapped in the energy of the earth that springs from within, you gaze at the infinite expanse of the universe. Earth and universe, inside and outside, finite and infinite. Everything becomes one.

This experience cannot be fully explained in words. You need to actually enter a starlit onsen, look up at the stars, and feel it for yourself. The emotion comes only from the experience.

Starlit onsen is a miracle created by Japan's nature. Abundant hot springs, a light-pollution-free environment, clear air. Only when all these are in place is this experience possible.

Starlit Onsen Can Change Your Life

Worries and anxieties certainly exist. But from the scale of the universe, they are truly small matters. Starlit onsen provides this perspective. It's an experience that broadens the mind and expands your view to the size of the universe.

When you visit Japan, be sure to experience a starlit onsen. Stay at a hot spring in the light-pollution-free mountains, enter an open-air bath at night, and look up at the sky. There, a starry sky unlike any you've seen before spreads out.

Wrapped in the warmth of the hot spring, feel the universe. This mystical experience will become an unforgettable memory for a lifetime. Starlit onsen is a bridge connecting the universe and humanity, something Japan proudly offers to the world.