yeunganson,

If you can't prove you have a regular income in Japan which they can seize in case of payment default, what should they give you a credit card ? The risk is too high for them.
For years now, I have 3 CC (2 Visa Sumitomo / 1 MasterCard form DCCard) in Japan with up to 1.3/1/1 million JPY credit on them. Didn't have any trouble to get the 1st one as I send a recommendation letter from my Cie attached to my application form. The others were also a piece of cake, simply because I already had one.

On another note, if you relocated in Canada for good, then you were supposed to give back your Alien card. Because your working situation changed and your working visa, even if not expired yet, is therefore legally voided.
Also, your alien card means nothing. It's valid for 3 years even if you have only a one year working visa. What counts is having a proper working visa.

Regards,