Via tokyohive:

We, avex group, and S.M. Entertainment Japan Inc. have had exclusive contracts for artists like BoA, Tohoshinki (TVXQ), and J-Min since the beginning.  We've been building a cooperative relationship, and right now, we're trying to build an even closer relationship. Including the aforementioned artists named above, we have recently made exclusive contracts with both SUPER JUNIOR and f(x), both of whom are already popular in Korea.  Both SUPER JUNIOR and f(x) will enter the Japanese market under S.M. Entertainment Japan Inc. and will also be signed under avex group as both a record label and a management agency.  We hope you can support the artists. As of now, Tohoshinki will continue forward with only Yunho and Changmin. We hope that you can support all of the mentioned artists: BoA, Tohoshinki, J-Min, SUPER JUNIOR, and f(x). -The all male group SUPER JUNIOR debuted in 2005 with 13 members. -In 2009, f(x), an all female group, debuted with 5 members. Source: avex