I thought maybe Sanmon Gossip never got a Taiwanese release (as a way if explaining the lack of popularity...) but it seems that that's not the case... It makes me interested to see what the general public in Japan (not just Ringo fanclub members) would choose as their favorite albums...
I think lack of promotion could be a big source, though--I'm sure other people here agree, but seeing her perform a song live is always what makes me rethink my opinions on her music
