Every year in April, a Shinto priest offers a prayer for the safety and prosperity of Lake Shikotsu for the entire year, in a prayer festival that marks the opening of the tourist season. The key monument symbolizing the lake opening has the meaning of 'the key that opens the door to Lake Shikotsu's tourist season'. Additionally, an offering of Himemasu (Kokanee salmon) fry, affectionately known as 'Shikotsuko Chip,' is also made. You can enjoy gourmet food and activities around Lake Shikotsu, and from around late April, swan boats and other attractions become available, and the area around Lake Shikotsu begins to bustle with many people out for a drive.