i notice that a number of people had no idea where to download japan music and stuff. thus i recommend this great place, jpopsuki!
What Do they offer?
and sometimes, you can find korean pop and chinese pop there too.
How To Download?
i admit that sometimes the torrent can be very slow when there's no seed and few peers.
Therefore, if you want to download items from artist like Ayumi Hamasaki, Koda Kumi, Utada Hikaru, Aya Ueto, BoA, Nami Tamaki, Rie Tanaka, Jolin Tsai, Yuna Ito, Erika Sawajiri, T.M. Revolution, High & Mightly Colors and Yui. Feel free to ask me, i might have what you need. my sister and i have a number of songs from these artist. I can upload in a direct link for you, which will be fasting then downloading through torrents.