Suzuki Sensei (2011)

Damn, somehow I cannot find the 6th season, so I decided to recommend you this one. Both dramas tackle the same issue (though the presentation are different) and radical in terms of way of thinking

Both stories involve a homeroom teacher who finds creative and unconventional ways to fix problems in the classroom and the students' personal lives.

Both deal with complicated and delicate issues in school from the teachers' perspective. No frills and unnecessary gimmicks, just gritty realism and smart narratives.

Both stories focus on students and a dedicated teacher with an unique learning approach. School Days with a Pig is drama/comedy and it's based on true events though.

Both psychological drama involving teacher and students. It's just that suzuki sensei can be the "I'lll shove my ideals down to your throat" type of drama.

Both shows are quality school dramas dealing with open-mindedness and freedom of speech, be either in scope of class and the society the students live in. Suzuki Sensei is a bit more complex and more realistic, though

Both drama feature school teachers trying to fix their classroom, sometimes using unconventional methods.

Both are rather deep and philosophical, set in a high school with a young, popular teacher as the main character. Both cover the relationship between the main teacher, his girlfriend, and a female student.