Gachi Baka! (2006)

The usual teacher with unlikely background and reform the delinquents. the difference is that Gokusen feature a female lead and all-boys school.

It have similar story (ex-delinquent turned teacher) and the teacher help the students to become better. GTO is a bit darker than Gachi Baka!

both have weird teacher that somehow transform the dynamic of the class and the students. Taiyou to Umi is more realistic than Gachi Baka!