So I read this manga some time back and I forgot its name. The story is about this boy he ...

So I read this manga some time back and I forgot its name. The story is about this boy he was lonely I think and he sent a written letter (I don't remember how but it wasn't by mail) it wasn't written for anyone specific but this other boy found it and he read it and replied and they became friends and one day they both met up and that's all I remember.