Taiyou no Uta
A Song to the Sun
A Song to the Sun

Has 10 episodes.Drama Wiki said:
It's the type of Romance/Drama that has both Lightheartedness and strong emotional impact. The theme alone shows how romantic it is: About a girl that sings under the moonlight.
Later on in the show, Kaoru, Kouji and his friends, forms a band known as Moon child.
http://wiki.d-addicts.com/Taiyou_no_Uta