A small volcano, 112 meters above sea level, jutting out into the Sea of Japan. From the summit, you can enjoy a panoramic view of Hagi's cityscape and the islands scattered across the Sea of Japan.
Kasayama is a 112-meter-high volcano located on the northeast coast of Hagi City, Yamaguchi Prefecture, and is designated as part of the Kita-Nagato Coast National Park. Formed approximately 10,000 years ago by volcanic activity, Kasayama consists of a lava plateau formed by lava flows and a scoria cone created by the accumulation of volcanic cinders scattered during the eruption. A small crater, 30 meters in diameter and 30 meters deep, remains at the summit, offering breathtaking views. You can see Hagi's cityscape, the islands dotting the Sea of Japan, and on a clear day, even Shimane Prefecture in the distance, allowing you to fully appreciate the magnificent natural scenery. Kasayama is also a popular trekking spot, with well-maintained walking trails leading to the summit, making it easy for anyone to enjoy a hike. There are also cool spots called 'kazefuki' (wind holes) on Kasayama. These are places where cold air blows out from gaps created when the lava cooled and solidified. Even in the summer, you can feel a refreshing coolness, making it a recommended summer retreat. At the foot of Kasayama lies Myojin-ike, a brackish lake. Myojin-ike is a brackish lake formed by the lava of Kasayama and the action of the currents, leaving a part of the sea enclosed. Seawater enters and exits through the gaps in the rocks; therefore, the water level rises and falls slightly with the tides. The pond is home to about 20 species of saltwater fish, including red sea bream, black porgy, and mullet. Kasayama is home to warm-climate plants such as Bakuchino-ki (Sterculia monosperma) and Tamashida (Nephrolepis auriculata), and the influence of the cool air from the wind holes results in the presence of cold-climate plants such as Kotaniwatari (Asplenium ruprechtii) and Hosoi-node (Dryopteris erythrosora). The coexistence of warm-climate and cold-climate plants is rare, giving the area significant academic value. Furthermore, there is a grove of approximately 25,000 camellia japonica trees at Toragasaki in the northwestern part of Kasayama. The "Hagi-Tsubaki Festival" is held here during the blooming season from February to March. Kasayama is a place rich in nature, offering a variety of ways to enjoy it, from trekking and sightseeing to plant and geological observation. Be sure to visit Kasayama and experience its magnificent nature.