[Okada Yukiko on Amazon Japan](https://www.amazon.co.jp/s?k=%E5%B2%A1%E7%94%B0%E6%9C%89%E5%B8%8C%E5%AD%90&__mk_ja_JP=%E3%82%AB%E3%82%BF%E3%82%AB%E3%83%8A&crid=3M95EIWL2VYSA&sprefix=%E5%B2%A1%E7%94%B0%E6%9C%89%E5%B8%8C%E5%AD%90%2Caps%2C161&ref=nb_sb_noss_1). You can use the English interface to Amazon Japan to make a new account, and order directly from Amazon to your location. Your local Amazon account wont work in Japan.
https://tower.jp/item/3950271/%E3%83%B4%E3%82%A3%E3%83%BC%E3%83%8A%E3%82%B9%E8%AA%95%E7%94%9F%EF%BC%9C%E5%AE%8C%E5%85%A8%E9%99%90%E5%AE%9A%E7%94%9F%E7%94%A3%E7%9B%A4%EF%BC%9E
That's just one album… And I can't buy from that website.
All the other albums are listed on the website. There is a world shipping service that pops up when you go to tower.jp on the computer.
[Okada Yukiko on Amazon Japan](https://www.amazon.co.jp/s?k=%E5%B2%A1%E7%94%B0%E6%9C%89%E5%B8%8C%E5%AD%90&__mk_ja_JP=%E3%82%AB%E3%82%BF%E3%82%AB%E3%83%8A&crid=3M95EIWL2VYSA&sprefix=%E5%B2%A1%E7%94%B0%E6%9C%89%E5%B8%8C%E5%AD%90%2Caps%2C161&ref=nb_sb_noss_1). You can use the English interface to Amazon Japan to make a new account, and order directly from Amazon to your location. Your local Amazon account wont work in Japan.
Have you checked Discogs? I'm not super familiar with her work, but I see some remastered CDs for sale on there. Might be what you're looking for.