J-Pop ah maybe J-Techno grr ok J-Dance ?

Perfume

http://en.wikipedia.org/wiki/Perfume_(group)

http://www.perfume-web.jp/

Repost: Updated to replace lost videos: You decide what genre they belong in or J-pop by default. As with Hello!Project groups such as Morning Musume the trio here only sing & perform the music/lryics produced/writen by someone else, but despite knowing such it doesn't detour me from supporting them. Discovered the group in 2008 and like most of the singles released to date. Japanese lyrics are easy to find, but not so much translated into English. However give them a try for some of the songs are "catchy" & might find your toes tapping. 

 Love the World (live)

Dream Fighter PV

Edge (live)

Electro World PV

Computer City PV