@azuremirage
Okay, I gotta know because manga is really painting Japanese culture in a light that I can't believe but is an exchange diary really a thing that people do? I'm actually wondering here because I've never seen any kinda tradition like this in North America and maybe this is a result of the environment I grew up in but normally people either talk about their thoughts or don't talk about their thoughts to each other.
I don't know if this exchange diary is a positive reflection of the Japanese mindset to try to communicate when communication is difficult or if it's a negative reflection of non directional confrontation.
The tradition is based on penpal where you write letter each other with / without knowing who they are. Well, you might not knowing that since you are a millennial when internet was there when you are born, and just use chat app to do that.
Heisei era, early 90's in Japan, before social media / message board / chat was a boom, there was a popular friend's clique activity called Exchange Diary (Koukan Nikki) where those group everyday rotate the book to every person, sharing their thought or activity. This activity is popular among girls. But somehow, it becomes romantic way when you do it with your lover. Sometimes the content is about their activity, sometimes about their state of mind, but sometimes they comment about that activity before writing their own diary. Also, this exchange diary is like facebook, they put their photo from photobox booth gluing in one page right after they take photo together.
Well, I think this friendship activity is never dying even Zucc create Facebook because in some chance, that exchange diary book is their friendship treasure one day.