Explore the Ruins of Ishiharadake Forest Park in Saikai, Nagasaki

Ishiharadake Forest Park in Saikai, Nagasaki Prefecture is a slightly mysterious place where the remains of a modern-era fortress still lie quietly in the woods.
This featured video takes you along the park’s well-maintained trails and lets you experience moss-covered stones, cool air, and shadowy underground spaces evocative of an atmosphere reminiscent of Laputa from Studio Ghibli's Castle in the Sky.
What makes it special is that it is not merely a mountain dotted with ruins, but a park where the ruins blend naturally into the landscape. Since you can encounter them as an extension of a stroll or forest bathing, known in Japan as shinrin-yoku, it feels comfortably approachable even for first-time visitors.
In this article, we will introduce the highlights of Ishiharadake Forest Park、including its history, as well as its well-maintained walking paths, restrooms, gazebos, cooking facilities, and camping areas.

Photo: Ishiharadake Forest Park in Saikai, Nagasaki Prefecture

Ruins from 125 Years Ago?

Ishiharadake Forest Park is a place where the remains of a modern-era fortress seem to melt into the forest itself.
The Ishiharadake Battery (Ishiharadake Hōrui) within the park is said to have been completed in 1899. As you walk, you can see that structures once built for defense now stand quietly, embraced by the trees.
On paper, it is a “Meiji-era remnant,” but when you stand there, you feel something stronger: the presence of time itself. Moss tracing the edges of stone, the hush of the surrounding woods, the cool, clear air. The Meiji era, which should feel far away, seems to breathe softly deep in the forest. That quiet sense of historical romance is this forest's greatest charm.

What Is the Ishiharadake Battery in Nagasaki?

As you walk through Ishiharadake Forest Park, you will come across the remains of the Ishiharadake Battery.
The term hōrui, often translated as “battery”, is best understood as a defensive position within the larger system of a fortress. The Ishiharadake Battery was one of the defensive installations built to protect the naval port. That is why the stone walls and shaped terrain remaining in the forest look less like scattered rubble and more like structures deliberately built for defense.

Photo: Sasebo Fortress remains (Ishiharadake Battery site) at Ishiharadake Forest Park in Saikai, Nagasaki Prefecture

An interesting point is that these defensive facilities did not just consist of buildings. You can see a variety of measures which were used to increase the defensive strength of the battery through the terrain itself, such as raised earthworks, trench lines, and stone-reinforced slopes. there is enjoyment to be found in searching for these traces as you walk. Simply gaining one new perspective makes the same scenery far more fascinating.

Highlights of Ishiharadake Forest Park

The appeal of this place is that the remnants do not push themselves forward as a “main attraction.” Instead, they blend naturally into the forest scenery. The green of moss, the gray of stone, and the dappled light through the trees. As these colors and textures layer together, it begins to resemble the world of Laputa.
Rather than large buildings, what you notice are traces such as stone outlines, steps, and subtle rises and dips in the ground. Because of that, discoveries follow one after the other as you walk: one here, one there, another just ahead.

Photo: Sasebo Fortress remains (Ishiharadake Battery site) at Ishiharadake Forest Park in Saikai, Nagasaki Prefecture

The stone surfaces can look softer when covered in moss, and then sharply defined when shadows fall across them. Even in the same spot, the impression changes depending on the time of day. Since the forest is quiet, you can clearly hear your footsteps and the rustle of branches and leaves, which makes the stillness feel even deeper.
Around the remnants, the air often feels noticeably cooler、conveying a shift in atmosphere rarely captured in photos. As a result, this is less a place where you “go to see ruins,” and more a place where you “meet ruins while walking through the forest.” That subtle sense of distance is what creates the Laputa-like feeling.

What Is the Enpei-bu Shelter Like?

The first major highlight of the video starts at (0:30) with the lowest-level enpei-bu shelter. The moment you step into the darkness, the air turns cool, and it becomes strikingly quiet, as if sound is being absorbed.
The word enpei (掩蔽) itself means “to cover and conceal.” In modern fortifications, an enpei-bu is often explained as a “concealed protective space,” designed to shelter personnel and supplies from shelling and other attacks.

Over time, both structure and materials evolved. In the Meiji period, stone and brick were used, and later the use of concrete became more widespread. That technological shift is part of what defines these shelters.
With the Ishiharadake Battery, there is not always enough information to state every detail of the enpei-bu’s original use with certainty. Still, the appeal of this section lies in the fact that the park has been developed to preserve the atmosphere of a fortress site, and that the “underground air” conveyed in the video leaves a strong impression as an experience. The quiet beyond the darkness feels far more intense than it does in photos.
To enjoy it safely, bring a light (your smartphone's light is enough) and be sure to wear comfortable walking shoes.

What Can You See at the Gun Battery Site?

As you reach the gun battery area, it quickly becomes clear that Ishiharadake Forest Park was developed around the Ishiharadake Battery site.
The city of Saikai also introduces it as an atmospheric fortress site, and one of the key charms here is how the outlines of stone structures remain within the forest’s stillness.

Photo: Sasebo Fortress remains (Ishiharadake Battery site) at Ishiharadake Forest Park in Saikai, Nagasaki Prefecture

The key discovery here is that the battery site cannot be reduced to simply “Where the cannons were placed.” On Nagasaki’s tourism websites, the Ishiharadake Battery is introduced as a battery completed in 1899, with remnants still preserved within the park. Once you know that background, walking the battery area makes the structures in the woods look less like mere “scenery,” and more like traces of their original role.
When those “outlines of history” connect with the atmosphere of the place, it lingers in your memory in a quiet, gradual way.

As you reach the gun battery area, it becomes easy to understand, just by looking around, that Ishiharadake Forest Park is “a place developed by making use of the Ishiharadake Battery site.” The outlines of stone structures remain within the forest’s stillness, and it is a point where you can strongly feel that this was not just a walking trail, but part of a modern defensive facility.

How to Enjoy the Campsite

Ishiharadake Forest Park is a park with historic ruins where you can also camp. The fee is 520 yen per tent per night, and reservations are required.
A good way to spend time here is to take a light walk around the remnants in the late afternoon to get used to the atmosphere, enjoy the forest’s quiet as it is at night, then walk again the next morning when the sunlight filters through the trees.
On a day trip, you may only glimpse the atmosphere, but if you stay, you will notice the expressions of the stone and the sounds of the forest gradually changing over time.

Access

■ Access from Nagasaki Airport by bus, train, and ferry (approx. 3 hours 10 minutes)
Nagasaki Airport (route bus “Nagasaki Airport to Nagasaki Station, via Nagasaki University East Gate and Peace Park”)
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Uematsu-higashi
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Shin-Omura Station (JR Omura Line and Sasebo Line, “Section Rapid Seaside Liner” bound for Sasebo)
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Sasebo Station
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Kujirase Terminal (ferry “Sasebo to Yokose-nishi,” bound for Yokose-nishi Port)
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Yokose-nishi Port
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On foot
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Ishiharadake Forest Park
Because airport bus operations and arrival times vary depending on the service and road conditions, it is reassuring to check the latest information on the official guidance and timetable for Saihi Bus (Nagasaki Airport Line) before you depart.
【Saihi Bus Official Website】bus.saihigroup.co.jp

■ Access from Nagasaki Airport by car
Nagasaki Airport
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Car (rental car)
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Ishiharadake Forest Park
Travel time may vary depending on road conditions.

What to See Nearby

One of the best things about the area around Ishiharadake Forest Park is how easy it is to combine the quiet of the forest with a different kind of experience on the same day.
If you want something more hands-on, the classic choice in Saikai is Nagasaki Bio Park. Official information highlights exhibits with few cages or fences and experiences where you can get close to and interact with animals, so it offers a visit that goes beyond simply looking.

Photo: Capybaras at Nagasaki Bio Park in Saikai, Nagasaki Prefecture

Another highlight is that the park offers animal feeding and interaction experiences. Capybara programs are especially popular, and in winter they may hold an event known as the “Capybara Open-air Bath.”

Opening hours are 10:00 to 17:00, with last entry at 16:00. The park generally has no regular closing days and remains open over the year-end and New Year holidays. They also note that temporary closures are possible in severe weather, such as typhoons or heavy snow. Since admission fees are listed officially as well, checking the latest details before visiting makes it easier to plan your day.
【Nagasaki Bio Park Official Website】biopark.co.jp

If you want to add more of a “travel” feeling, Huis Ten Bosch is another must. Modeled after European streetscapes, the park has an atmosphere you can enjoy just by walking around. In the daytime, you can take in canal-side views and architectural details. At night, the illumination transforms the mood completely.

Photo: Huis Ten Bosch in Nagasaki Prefecture

In particular, the illumination event “Kingdom of Light” is promoted as a year-round attraction, with highlights that change by season and area.

In winter, there is also a limited-time event called “World of Silver,” which offers a seasonal way to see the entire town in a different light. Since the event period varies by year, please check in advance.
For access, it is said to take about 5 to 7 minutes on foot from JR Huis Ten Bosch Station to the entrance, the Welcome Gate, making it easy to include even on a train trip. If you move from the quiet of Ishiharadake to the bright spectacle of Huis Ten Bosch, the tone of the same day’s experiences changes dramatically.
【Huis Ten Bosch Official Website】https://www.huistenbosch.co.jp

Conclusion

The charm of Ishiharadake Forest Park is that it is an easy place to walk trough as a forest park, yet during your stroll you can suddenly sense the presence of Japan’s modern era.
The cool air of the enpei-bu shelter, the outlines left at the gun battery site, and the quiet you can savor at the campsite. Even within the same forest, the density of the atmosphere changes from place to place. It is so interesting that before you know it, your walking pace slows down too. If you watch the video beforehand as a way to preview the atmosphere,　you will notice more moments of quiet recognition once you are there,　and your walk will become even more enjoyable.
Whether you simply want to walk in the woods or you are looking for a slightly different destination, this is a place where you can taste a quiet, out-of-the-ordinary experience. It is the kind of spot that makes you think on the way home, “I want to walk through that cool air one more time.”

Reference site for Ishiharadake Forest Park: https://www.city.saikai.nagasaki.jp/kanko/theme/spot/1/4942.html