was the second Japanese artificial satellite which was put into orbit, after the country's first satellite Ohsumi.[1] The satellite was sent into orbit on 16 February 1971.[2]
Just like Ohsumi, the launch was a project by the Institute of Space and Astronautical Science at the University of Tokyo (UTokyo). The name of the satellite means "light blue", which is the school colour of UTokyo.[3] Three more satellites with the same name were subsequently launched by the university. The last of them was launched on 17 February 1980.[4]