Mature romance recommendations?

So when I say mature I'm not talking Coffee and Vanilla and Shanai Marriage Honey mature lol. I didn't really like either of those two all that much because they moved too fast and didn't have any relationship or character development. I more so mean a romance that takes place between college age and older leads. I also like when the romance is slow and gradual, as in there is good relationship development. They don't go from 0 to 100 like in the two I mentioned. I also really like when there is a good storyline outside of the romance as well. I just finished Nodame Cantabile for example and I absolutely loved loved loved it. I liked that there was depth, character growth, and an interesting plot. Another one that I loved with similar vibes was Buzzer Beat. So basically I am looking for a drama with a good storyline, emotional depth, character and relationship development with romance as the icing on the cake. I hope that makes sense. I know it's pretty specific but I have a void after finishing Nodame Cantabile.

I've also seen:

Koi ga Heta demo Ikitemasu 

Koi wa Tsuzuku yo Doko Made mo 

Kyou wa Kaisha Yasumimasu 

Totsuzen Desu ga, Ashita Kekkon Shimasu 

Pride (2004) 

Thank you for the recommendations :) I am definitely adding Orange Days, Pride and Nigeru Haji da ga Yaku ni Tatsu to my plan to watch list. These look like they are right up my alley. If anyone else has recommendations please keep them coming. I am really appreciating  Jdramas these days and specifically ones like this. 

as your starting, you can watch Koisuru Hahatachi for the recent drama

+1 Orange Days- I LOVE that drama

Destiny-Like Love~ and pretty much anything with Saito (Mr. Steal-your-girl) Takumi and the romance tag. It's guaranteed he will be going after some woman.

Hirugao and the movie 

Kimi wa Petto 2003

Majo no Jouken

Kamisama Mou Sukoshi Dake

Aishiteiru to Ittekure ~ this is hands down, the most romantic jdrama I have ever watched; the angst is A1