Confused about internship requirements

I�fm a student at a Canadian university and am looking to do a long-term, paid internship in Japan this year. I am of Japanese descent but a Canadian citizen, and from what I�fve read on the Japanese Immigration Services Agency website, it seems that paid internships in Japan can only be done if the internship contributes to a student�fs academic studies, �gsuch that credits can be earned and the content of the internship must be related the student�fs major�h. How accurate/stringent is this? What about companies that don't require internships to be transferred as credits? Is this a case-by-case thing or is it enforced by Immigration for all foreign students? I�fm not aware of an internship = credits system at my school, and the internship I�fm looking into is not 100% related to my major. Feeling a bit discouraged by these requirements. Any thoughts or advice are welcome.

long story, short:
strictly saying, there is no "paid (salary) internship" in Japan.
when you get some money (or an equivalent or any rewards) by exchanging your labor, it is "work". so, internship can be considered as one of educational programs by which students learn real society.
so, those interpretation help you and prevent you from illegal low salary working.

my practical advise is that, find internship in one of famous companies, which are listed in Tokyo Stock Exchange. they should be OK.