[2008] This Japanese artist = This English Artist

[bondingo]

I agree with two of yours so I chose those as well. I really don't think any of these are that much like the ones I compared them to, but I see definite similarities:

Hamasaki Ayumi- Madonna
Amuro Namie- No comparison (maybe Janet Jackson, but not really)
Koda Kumi- Dirrrty era Christina Aguilera or maybe even Fergie
MISIA- Mariah Carey (when she was good) or Celine Dion
Shiina Ringo- P!nk or Alanis Morissette
Salyu and/or KANA- Bjork
Tommy heavenly6- Avril Lavigne (although Tommy is infinitely better)
Yaida Hitomi- Dolores O'Riordan (from The Cranberries)