There are various Japanese dating websites online. A quick Google search will take you to them.
However, there’s no guarantee she’ll be rich. Is that certain quality a must?
Other things you should try to do if you’re looking for a Japanese girlfriend:
– Keep an open mind about Japan and its culture
– Make some kind of effort to learn Japanese, even if it’s only a little
– Like women of any ethnicity, treat her with respect and listen to what she has to say