Tatebayashi Miharu

The only time that Miharu appears in the game is at school, and she seems to randomly bump into you. However this isn't random. In Oshiete Your Heart, Miharu will always appear when you have two consecutive "slightly unhappy" dates.

The following pictures are for the first time you bump into Miharu.

Miharu is wearing a summer uniform in the summer, and winter uniform in the winter.

The following pictures are for the second and third times that you bump into Miharu.

Supposedly, if you bump into her three times, and go all the way to the end of the game (third year) without making any other girl happy, you will end up with a confession by Miharu.
[I've tried, but never successfully got this ending.]

If you bump into Miharu three times before the third year, and you don't go to the park to confess to any other girl, she will call you in the third year (I think autumn). Then you will go on a date with Miharu, and she "decides" if she will confess to you. If she does, then she will give you a note at the end of the third year.