this is a beautifully told story, i could picture it all in my mind like a brightly coloured dream, a book, it really is well told and delicate.
Maybe you need to visit Japan, maybe not(?) to find those two, but maybe to find yourself as you are a little lost in this other experience, which is strong.
The people in your dream/memory could be linked to you in any number of ways, and one day you will understand. Have you ever done hypnosis with a therapist? maybe that could help you get some peace on this/ about this. Also maybe the people in the dream are around you already...? Have you talked to anyone close about the dream?