It is a story of the night sky set in Yakage Town, a small mountain town in Okayama Prefecture. Yakage is a quiet place with abundant nature in the countryside. At night, it is covered with stars. Now, the rice planting is over and the calm days before the rainy season continue. When the sun goes down and it gets dark, fireflies begin to dance in the stream beside the rice fields, and the starry sky moves from spring to summer.
This area around the Seto Inland Sea, including Yakage Town, is known as a perfect starry sky observation area because the air is clear and stable sunny days continue. It is a place where not only starry sky lovers but also the world's top observatory will be set up. Let's go on a journey to explore the starry sky at night, surrounded by the sounds of nature!

This content is not licensed.

VR Video Specifications

Resolution Type Audio Duration License
4K 8K 12K 16K 2D 3D 2ch 5:00 

Firefly in Summer

Saigoku Highway Journey

Saigoku Highway is one of the highways in the Edo era, and this is what we call the Sanyo Road. It is a long way from Kyoto to Shimonoseki. Almost in the middle of that journey are post towns such as Yakage and Ihara in Okayama Prefecture. Yakage-juku was especially prosperous. Even now, the old townscape remains, and it is a prefectural designated townscape preservation area. The former Yakage Honjin of Ishii was ordered to become a "Honjin" in accordance with "Sankin-kōtai", and remains as an important cultural property.
There are many places around this area that are famous for their good visibility. For example, it is Bisei-cho, Ihara. The name indicates that the stars are beautiful. Even on a map, there are many facilities with names that are reminiscent of “stars”. On the mountain with the best view is the Bisei Observatory, and a large telescope with a diameter of 101 cm is open to the public. Also, starry sky enthusiasts are gathering here, taking photos and looking through telescopes.
The top of the mountain that stretches between Yakage and Asakuchi is even more authentic. At the forefront of astronomical research, such as the 188cm telescope at the National Astronomical Observatory of Japan and the 3.8 meter telescope "Seimei" at Kyoto University, are located here.
One of the reasons for the large number of astronomy-related facilities is probably the high weather rate. Looking at the rankings on sunny days of the year, prefectures around the Seto Inland Sea dominate the top of list. (However, Okayama Prefecture is not mentioned in that.) According to the prefecture, "No. 1 days with less than 1 mm of rainfall". Either way, there is no doubt that the probability of clearing is high.
Low-altitude sky areas are always bright due to the large cities lining the Sanyo Road. It may be annoying for those who just want to see only the stars, This is the best location for those who want to enjoy with the nightscape. In particular, you can see the night view of Kurashiki and the Seto Inland Sea from Mt. Yoshozan.

Country Side

Astronomical Observatory in the Countryside

From the Seto Inland Sea, go north on Prefectural Road No. 64 and go through the long Youshozan Tunnel, you will suddenly be surrounded by mountains on all sides. That is Yakage Town. Rice fields are spreading. The scenery with shrines dedicated to the gods everywhere is truly unique to the Chugoku region. There is a waterway in the middle of the rice field, and the National Astronomical Observatory of Japan and the astronomical observation dome of Kyoto University can be seen on the mountain. Just in the evening, the landscape becomes a silhouette, reminiscenting of Hawaii's Mauna Kea. Now is the end of May. Rice planting is almost finished, but the seedlings are still small, so the water surface looks like a mirror, reflecting the color of the sky and is beautiful. Soon the night came and the stars began to shine.

Early Summer Fireflies

There is a place called "Unai Firefly Park" beside Hoshida River. Literally, fireflies are flying in the season. In addition, the surroundings are dark and there are only rice fields. The sound of frogs, the firefly's dance and the blink of a star are probably one of the most calming combinations for Japanese. The summer triangle is already visible in the eastern sky. The season is already summer.

Observatory and the Milky Way

The dome of the observatory operated by Kyoto University contains a 3.8m telescope, which seems to be the largest in East Asia. Mainly using infrared wavelengths to observe exoplanets. In these cutting-edge telescopes, the image processing of the data received by the electronic sensor may be exclusively for observation. The summer Milky Way has just risen above the dome. Near the zenith, the night view of the city is less affected by light pollution, and the stars are clearly visible.


The highway of Yakage-juku extends almost east and west along the Oda River. It is a well-maintained road that retains the atmosphere of the time. Honjin and Waki-Honjin are located along the highway, and both are designated as national important cultural properties. It is only here in Japan that both Honjin and Waki-Honjin are designated as multiple sentences. The Honjin is a hotel dedicated to the authority of the time, such as Daimyo and Hagimoto. So, accommodation for ordinary people was not allowed. There is a record that the Honjin of Ishii in Yakage was used by the Shimazu family, the Kagoshima feudal lord, and the Mori family, the Hagi feudal lord. At present, it is possible to tour the inside as a heritage with high documentary value.


It is a mountain at an altitude of 405m that straddles Yakage Town and Asakuchi City. If the weather is fine, you can see the other side of Shikoku beyond the Seto Inland Sea. There is an observatory park near the summit, and it is known as a night view spot. Kurashiki City is located in the southeastern direction, and at night you can see the nightscape where the Mizushima factories emit brilliant light. The observatory is located next to Mt.Yoshozan. You can't see the observatory from here, but you can expect a good starry sky as well.
If you want to enjoy the nightscape and the starry sky at the same time, you may want to visit Yoshozan at night.
The night is dawning from the east. It is almost sunrise.