It's not that this one is prequel or sequel to Second Years or March 15, it's just they feel the same way.

Manase always like to draw this kind of relationship between the second year trio, it's so strong meanwhile so easy to break. I wonder if anyone would like to translate 心かくれんぼ(http://www.pixiv.net/member_illust.php?mode=medium&illust_id=45976842), it is my favorite of all his/her works.