Glad you brought up the topic!
I took a Japanese gender and sexuality course while attending Kansai Gaidai last year, and it was pretty eye opening!
We talked about the korean women who suffered under the Japanese 'comfort woman' system during WW2, current lesbian and gay lifestyles/lack of visibility, and general sexual education students in japan receive (or the lack thereof).
It was really shocking to me when we discussed just how much women there lack agency when entering in and maintaining relationships. Some female japanese dormmates were also in the class but were often silent. When discussing contraceptives though they shared how little they really knew or were taught about by family and school.
One girl who was close to me was shocked that so many of us use and promote the pill, (somewhere like 5% or less use it in Japan), because her mother told her that if you ever take it you can NEVER have kids again. (i felt bad for her, we set her straight)
Fun fact: The pill was banned until 1999 in Japan (that's 50 years later than the US)
Women are also expected to just allow men to decide whether to use condoms or not, and to never contradict their decision. Yeah....no that would never fly with me.
Wish i would still take those courses D:
(Sorry if this was so wordy all!!)