How to book Japanese artists?

Say i want to organize a concert or festival with Japanese artists, like L'Arc~en~Ciel or Hikaru Utada or any of the other artists that are constantly topping the Japanese charts.
How would i book such artists? Should I approach their recordcompanies or are there special management-agencies to turn to?

Does anyone have (web-)adresses or phonenumbers which could be usefull to me?

Thanks in advance,