Yamaguchi Kumiko is next in line to be the boss of the Kuroda Ikka yakuza clan due to her parents' death. However, fresh out of college, Kumiko decides to pursue her lifelong dream of being a teacher. Now hired as a mathematics teacher at an all-boys school, Kumiko must hide her true identity. She's assigned to class 3D, inhabited by the worst of the worst delinquents. Popularly called "Yankumi" by her students, she tries her best to gain the respect of and offer help to these students who'd like nothing more to make her life a living hell.
Natsuzora and Run and Gokusen have a very different style (the first one is more about romance and drama, while the other is more about comedy and some action), but I guess the male student x female teacher relationship is a rare enough theme to warrant a recommendation, so here it is.
Both are stories about passionate teacher, dealing with class full of deliquents. Students are always causing a lot of problems, yet they are slowly reformed by the unusal way of teaching, that new teacher employs.
Both main characters are good fighters.The main difference is their gender, and the gender of potential readers (Rookies is shounen while Gokusen is Josei)
Four gorgeous guys, one fabulous mansion and one challenge - turn the landlady's niece into a perfect lady and live rent free; fail and their rent will triple! Surely this task will be no problem for Ranmaru Mori, Kyouhei Takano, Takenaga Oda and Yuki Tohyama, who are lauded as the princes of their high school and have girls dropping at their feet daily... right? The boys' dream of rent-free living comes crashing down when they meet Sunako Nakahara, the girl they must transform. Sunako has devoted her life to solitude, preferring the company of anatomy mannequins, horror movies and the darkened seclusion of her bedroom to the presence of the ‘dazzling creatures' that cause her to have violent nosebleeds. Flushing her out into the light might prove to be more than the boys can handle!
Male leads in both Unbalance x 2 and Gokusen happen to fall in love with their homeroom/math teacher (a female one in case you wonder). They are both quite serious about it, but it takes them a lot of maturing to achieve their goal which is, make their object of affection feel the same way about them. Unbalance x 2 is mostly driven by drama (lots of drama) and romance, with some comedy on the side, on the other hand Gokusen is mostly driven by comedy and fights, though the romance is still there. Both of those series resolve the romance part pretty well, so if you liked one of them because of the romance, then you'll probably love the other one too. Just keep in mind that Unbalance x 2 had those bits of ecchi and mature undertones (occasionally).
Daichi Shinigawa is a typical delinquent who wants nothing to do with high school. However, bespectacled Hana Adachi, the class representative, will do anything in her power to make sure Daichi participates in whatever events the school has to offer. If she has to surprise him in the boy's bathroom to get him to go on the school field trip, so be it! Daichi is confused as to why a class rep would care so much about a troublemaker like him; what could be the reason behind her actions?
In both titles the main heroine is very energetic and passionate, daughter of the yakuza household. They try to live a normal life without employing the powers of their families. Both are very strong fighters, but try to avoid fighting as much as possible.
In both cases manga deal with deliquents, changing their ways for one reason or another. Both are very good school life stories with lots of comedy mixed in.