Nana

In the story, since both main characters have the same first name, to differentiate one Nana to the other, Nana Osaki affectionately called Nana Komatsu "Hachi", because she thinks Nana Komatsu behaves like a dog, faithful but sometimes annoying. This is actually a play of word. The female name "Nana" is a homonym of the Japanese word "nana" that means "seven", and while "Hachi" is a common dog name in Japan, it is also a homonym of the word "hachi" that means "eight".

When Nobu is playing his tape to Nana the first time, you can clearly hear a bass guitar in the song. This is not possible at that time since Ren left for Tokio long before that and Shin wasn't in the band yet.