Since it hasn't been made explicitly clear yet - you can't get a student loan from the Japanese government.
I would agree with tomani's (2) - if you have an offer from a Japanese university already, you should contact them directly to ask about exact tuition costs (and any potential reductions), and scholarships available for foreign students (some many be local/specific), as well as costs outside tuition (typical costs for living in dorms/living out, recommended budget, etc - which will vary by location). Also think about "startup" costs (travel costs, deposit for your accommodation, whatever chunk of the tuition they want up front, etc).
As well as the university in Japan, the university you're attending in Canada probably has a person or persons who looks after scholarships/grants/etc who might be able to help with sources of travel/study abroad money on that side.