I know this topic has probably been covered, but the search engine says "credit" and "card" are too common words, so gives no results.

I am not married to a Japanese citizen and just live in Japan with a year-to-year visa. I have a steady income, above the standard eikaiwa/ALT salary. I've been living in Japan over a decade (although not in a row). I pay my taxes, health insurance, pension, and other bills.
I have applied for credit cards in the past, but have been rejected. I applied at two major banks and JP Bank.
I've heard that Rakuten might be a good option, but I've also heard that if you apply for a credit card and get rejected, you should wait at least 6 months before applying again.
Any suggestions? I don't understand why an institution would be afraid to give me a credit card. I also have a great credit rating in my native country.