Another attraction of Lake Mashu is the deep blue color of the lake, known as "Mashu Blue," which can only be seen on sunny days. This blue color is created by the special conditions under which sunlight is reflected and absorbed, due to the unique topography of Lake Mashu, which is almost unaffected by the surrounding mountains and trees. For this reason, Lake Mashu is even more beautiful on sunny days. To enjoy Lake Mashu on a sunny day, it is recommended to check the weather forecast and visit early in the morning. The air is particularly clear on summer mornings, and the sunlight shines directly onto the lake's surface, making the "Mashu Blue" more vivid. The panoramic view of the lake from the observation deck is spectacular, and the contrast with the lush green mountains surrounding it will delight the eyes of visitors. In addition, binoculars are installed around the observation deck, allowing you to observe the lake surface and surrounding scenery in even more detail. Sunny days are also a great opportunity for photography. The blue color of Lake Mashu varies subtly depending on the season and time of day, so you can capture a new look every time you visit. Especially in autumn, the contrast between the autumn leaves and the "Mashu Blue" is beautiful, attracting many photography enthusiasts. On a sunny day, Lake Mashu is truly a work of art woven by nature.