Japanese companies usually has .co.jp domains. There are only one .co.jp domain per company and it must be registered as a Japanese legal entry to receive this domain. For companies wishing to have more Japanese domains, there are .jp domain.
If you are Japanese entity wishing to have .co.jp domain or non-Japanese entity but wish to have .jp domain, please contact PSPinc.
http://www.pspinc.com
or USA-800-232-3989 or USA 425-957-0462