10 dramas/movies where one of the leads writes a love letter to the other lead. (Any lead character counts and it doesn't matter if the letter is ever given or not).
3. Girl from nowhere- In the 2nd last ep. , the fl of the story(not Nanno) writes a letter to the ml while still in school, which is put in the time capsule. The letter is read when the time capsule is opened at their reunion years later.