Who is Akari's father?
This board is not very active, however as this film was recently made available for streaming by NetFlix in the US, perhaps somebody will see this question and have an answer.
At the beginning, some mention is made of Akari's father, but through the rest of the film his identity is not made clear (at least to me) although some possibilities present themselves.
First, notice that Akari uses her mother's family name. I think this could be understand to mean she was born out of wedlock -- I wonder how much stigma this might carry in Japan.
So one theory is that Kazuo is her father -- but her mother knew Kazuo in high school, so it seems highly unlikely she could have obtained an advanced university degree having gotten pregnant in high school (unless she gave the baby up for adoption which clearly did not happen).
The other theory is that Gotetsu is her father -- however in that case, I would think Akari would have his family name. Although I can see how if her parents were never married, this might not have happened. Again, a more thorough knowledge of Japanese culture might help.
Probably I missed something obvious.