 If you liked
Sakamichi no Apollon
|
 ...then you might like
Blue Giant
|
Both mangas are about jazz and musicians.
Also both deal with friendship.
If you like jazz and Blue Giant, you'll definitely like Sakamichi no Apollon and viceversa.
both are based around jazz, both have a pretty sad/angsty ending and a romantic relationship of some kind is established in both with the mc's