Iihi-tabidachi means “Good day, good start”. in 1978, it was composed by Japanese pop singer, Shinji Tanimura and sung by Momoe Yamaguchi. Momoe Yamaguchi was an immensely popular idol at the time, and many people still like her to this day.
The song is also a familiar melody to many Japanese people, as it is played when the bullet train(Shinkansen) arrives at the station.
Here is sheet music.