This is an event which takes place for three days in early October, it began with activities to conserve the endangered marimo algae of Lake Akanko. Marimo algae grow in fresh water and gather in large numbers to form green spherical bodies. It takes more than 100 years for natural marimo algae to grow to a diameter of 10cm, but the marimo algae in Lake Akanko are the largest in the world, growing to a diameter of 30cm.