Hi John,
You will need to Download the Japan Dial Plan :)
Voice and Unified Communications > Cisco International Dial Plan > Unified Communications Manager International Dial Plan (IDP) > 3.1(5)
http://tools.cisco.com/support/downloads/go/ImageList.x?relVer=3.1(5)&mdfid=278719042&sftType=Unified+Communications+Manager+International+Dial+Plan+%28IDP%29&optPlat=&nodecount=29&edesignator=null&modelName=Cisco+International+Dial+Plan&treeMdfId=278875240&modifmdfid=null&imname=&treeName=Voice+and+Unified+Communications&hybrid=null&imst=null
Deploying Dial Plans for 5.0(1) and Later\r\nReleases
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/idp/504_423/deploy/DPLinux.html
Hope this helps!
Rob