I feel like Japanese music in general helped me listen to more genres. At first I didn't see myself listening to R&B but when I heard the beats in micro genres from 90s-2000s in jpop I just HAD to listen to the blueprint.
My favorite r&b singer right now is Crystal Kay. She is an icon, she's African American and Korean and she in Japan I think. She also makes songs in Japanese and English she's an icon honestly.

