[Yamanashi, Yatsugatake] Grand Mercure Yatsugatake Resort & Spa! Firefly release experience and new activity "Billicker" available only on weekends in June.

Grand Mercure Yatsugatake Resort & Spa is an all-weather amusement hotel located in Oizumi-cho, Hokuto City, Yamanashi Prefecture. Situated at an altitude of approximately 1,000m, nestled in the majestic foothills of the Yatsugatake Mountains, it is a resort that can be enjoyed by a wide range of guests, from families to adults seeking relaxation(*).

It won first place in the 101-300 room prefecture category of the "Best-Selling Hotel Award" at "Jalan OF THE YEAR 2024". It features an all-weather kids' space "Mori no 8", play equipment such as bouldering walls and drift tricycles, and an executive lounge, making it a hotel where guests can enjoy themselves from check-in to check-out without worrying about the weather (*).

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

Grand Mercure Yatsugatake Resort & Spa is a resort hotel that caters to a wide range of needs, from families with children to adults-only getaways.

Grand Mercure Yatsugatake Resort & Spa will be holding a "Firefly Release Experience Event" for families on weekends only in June 2026 (*). * See

Grand Mercure Yatsugatake Resort & Spa Official Information

The beginning of summer is a time for families to create a future where, when their children grow up, many more fireflies dance in the forest of this hotel. That is the "Firefly Release Experience Event" at Grand Mercure Yatsugatake Resort & Spa (*).

In the past, many fireflies lived in the stream that flows through the hotel grounds. With changes in the environment, their light has gradually disappeared, and now the number you can see is limited. That is why tthe hotel has started an initiative to cultivate the "firefly forest" once again together with its guests.

* See " Grand Mercure Yatsugatake Resort & Spa official information "

At the event, families can gently release fireflies into the stream flowing along the walking paths on the grounds, creating a magical moment of soft glow. The event こalso includes easy-to-understand explanations about firefly ecology, making it a fun and educational experience for children (*).

Whether you're a calm 12-year-old in upper elementary school or a boisterous 6-8 year old, this is a time for everyone to connect with nature in their own way. The whole family can share the same scenery and create lasting summer memories.

* Based on official information from Grand Mercure Yatsugatake Resort & Spa .

Because this program is only available for a short period in June, you'll want to carefully choose your visit date. We recommend aiming for a weekend and making your family reservation early.

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

The main appeal of this program is that it's not just about releasing fireflies, but also about learning about the natural mechanisms necessary for fireflies to live (*). * See

" Grand Mercure Yatsugatake Resort & Spa official information ".

For fireflies to survive, a delicate balance in the natural world is necessary.

Only when all these conditions are met can fireflies continue their life cycle. Learning about the delicate balance of nature—that "clean water alone is not enough," "the presence of freshwater snails is essential," and "too much light is also detrimental"—to children is a unique educational value of this program . (*)

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

Unlike gaining knowledge from books or the internet, this is an experience of gently releasing adult fireflies into the forest with your own hands. The sight of tiny lights flying from your fingertips into the forest will surely be a memory you'll never forget (*). A

12-year-old elementary school student might even be able to use the knowledge they've learned about firefly ecology as the theme for their independent research project. A mischievous boy aged 6-8 might find this direct interaction with nature sparks a new interest. Here, you'll find an experience suited to each child's stage of development.

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

This program is not only something that children should experience, but also an opportunity for parents themselves to re-examine their relationship with nature. The time spent with family to think about the mechanisms of nature and the interconnectedness of life, which are often forgotten in daily life, is a valuable experience for adults as well.

For men who are often busy with work and have little time to spend with their families, and for women who are busy not only with work but also with childcare and housework, the time spent engaging with nature with their families will be a special time to step away from their busy daily lives.

What makes the "Firefly Release Experience" at Grand Mercure Yatsugatake Resort & Spa special is that it's not a one-time experience (*).

*See " Grand Mercure Yatsugatake Resort & Spa Official Information "

If the environment is suitable, the released fireflies may breed, and in a few years, we may once again see the sight of fireflies dancing in the stream. The appeal of this program lies in the fact that families can participate in a story of light that leads to the future, where the fireflies they released this year may continue to glow in the hotel's forest next year and the year after.

How about making Grand Mercure Yatsugatake Resort & Spa your family's go-to summer getaway? A place you can return to next year and the year after, wondering, "Are those fireflies we released still there?" (*). A regular summer trip that you visit with your family every June. This program might just be the start of a new family tradition. It 's an experience where you and your family can work together to create a future where even more fireflies dance in the forest when your children grow up.

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

For a stay centered around the firefly release experience, the hotel's other family-friendly facilities will be a great help.

• All-weather amusement facilities "Mori no 8" and "Mori no Lounge"
• Kids' athletics, bouldering, drift tricycles (first hotel in Japan to introduce this feature)
• A starry night sky viewed from the rooftop observation deck (a nature experience at night)
• All-inclusive pricing system (includes meals, drinks, and activities)

One unique way to spend your stay at this hotel is to enjoy a firefly viewing experience at night, followed by morning views of the Yatsugatake Mountains from the rooftop deck (*).

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information ".

Grand Mercure Yatsugatake Resort & Spa will be introducing a new activity called "Billicker," which can be enjoyed by families in a private space, starting in early July 2026. (*)

*See " Grand Mercure Yatsugatake Resort & Spa official information "

Billicker is a completely new activity that lets you enjoy billiards on a dedicated court (6m x 3m) using a soccer ball. As of the time of writing in 2026, Grand Mercure Yatsugatake Resort & Spa will be the first hotel in Japan to offer this unique activity. (*)

*See " Grand Mercure Yatsugatake Resort & Spa official information "

The basic rules of billiards are to move the cue ball (white ball) using a hand other than your hands, and try to get the object balls (balls with colors and numbers) into the pockets (goals) to score points. (*)



The appeal of Billiards lies in its versatility, allowing for various ways to enjoy the game, whether it's a serious one-on-one match or a team competition between family members. The fun is multiplied many times over by using different body parts and bindings, not just the feet, but also the head, buttocks, waist, heels, and more.
* Based on official information from Grand Mercure Yatsugatake Resort & Spa .

With a little creativity in the rules, such as "Dad only uses his heels" or "Mom only uses her head," this activity can be enjoyed by people of all ages. It's a fun way for 12-year-old elementary school children, mischievous 6-8 year old boys, and adults alike to laugh together.

As an activity that can be enjoyed indoors even on rainy days, it's sure to help create new family memories. Scheduled to begin in early July, this new content is a must-have for your summer family vacation plans. (*)

* Based on official information from Grand Mercure Yatsugatake Resort & Spa.

One of the charms of this hotel is that you can enjoy different experiences each month, such as firefly release experiences in June and billiards from July onwards. The style of choosing and enjoying special activities that are only available during the month of your visit is a mechanism that encourages repeat stays. (*)

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

Another major attraction of Grand Mercure Yatsugatake Resort & Spa is its easy access from the city center and the cool highland climate unique to its 1,000m altitude (*).

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

Just a two-hour drive or train ride from Shinjuku Station in Tokyo will take you to a plateau 1,000 meters above sea level. Being able to immerse yourself in a world 7 degrees Celsius cooler than Shinjuku Station is a major attraction for summer travel. (*)

It's convenient to travel by car in about 15 minutes from the Nagasaka Interchange on the Chuo Expressway, or by shuttle bus from Kai-Oizumi Station on the JR Koumi Line. Its location makes it easy to incorporate into weekend family trips or 1-night, 2-day plans for those with weekends off. (*)

*Refer to " Grand Mercure Yatsugatake Resort & Spa official information "

Even in the height of summer when temperatures in central Tokyo exceed 30°C, the Yatsugatake plateau enjoys comfortable temperatures in the low 20s°C. This climate, which allows families to enjoy outdoor activities while also being mindful of children's energy levels, makes it an ideal summer family travel destination. (*)

The Yatsugatake area, known as a summer resort, offers a pleasant stay for families from the firefly release season in June through the summer vacation travel season.

*Based on " Grand Mercure Yatsugatake Resort & Spa official information "

Grand Mercure Yatsugatake Resort & Spa is an all-weather amusement hotel located at an altitude of approximately 1,000m in the Yatsugatake Mountains. The "Firefly Release Experience Event," held only on weekends in June 2026, is an interactive program that families can participate in, offering a special time for both children and adults. Participants

will learn about the "clear stream, river snails, and darkness" necessary for fireflies to live, and then gently release adult fireflies into the forest with their own hands. It is sure to become a special place for families to return to next year and the year after, wondering, "Are the fireflies we released still there?"

A new activity, "Billicker," is also scheduled to start in early July. You can enjoy a time filled with laughter with your family at this summer highland resort. Just about two hours by car or train from central Tokyo, why not visit this cool world 7℃ below Shinjuku Station with your family?