Teaching License Requirements

Hi there! I've searched around on the forum and elsewhere and found a lot of information about the requirements to get a teaching license in Japan, but would like to have a few things clarified, if possible. To be clear, I am interested in teaching subjects other than English, such as math or physics, at the upper secondary school level. I am currently studying at a Canadian university and will soon be finished a BSc degree with a specialization in mathematics.

I know that a certain number of university courses must be taken in both teachable subjects (math/other sciences, in my case) and education in order to get a teaching license. Does anyone know if it is necessary for those education courses to have been taken at a university in Japan? Would I be able to get a teaching license if I have degrees from a Canadian university?

After finishing my BSc, I will have the option of taking a two-year post-baccalaureate degree to get a BEd. Do universities in Japan have similar programs for degree-holders who would like to get a BEd and become teachers? Or would I have to complete a four-year program in Japan if I wanted to get a BEd from a Japanese university?

This topic straddles working and studying, so I apologize if I put this in the wrong section.
Thank you for your help!

Unless you are aiming at an international school, you're going to need a degree and license both granted from a Japanese university. That also (obviously, I hope) means very high language fluency, since you will be teaching in a public or private school here, and kids have practically zero English ability.

A couple of posters on GaijinPot web site have mentioned that they went through that particularly arduous route, so you might want to fish for them, if you are still interested.

A teaching license from Canada, plus 2-5 years of experience there, will make you eligible for teaching any subject at an international school (in English).

Great, thank you so much for the info! I'll look around the forum to see if I can find those posts.
And another question I asked in the OP: what about education degree programs for those who already have a Bachelor's? Is there a way to get through a Japanese BEd program faster, or is a full four years necessary?

No idea. See if your school has any exchange system of credits with a school in Japan.

My big question though is this: can you take classes taught only in Japanese?