There is a great little plugin for Firefox that makes the browser display sites as if it were a mobile browser. I have used user agent switchers to check Safari and IE in Firefox but this is the first time I have been able to do it for Japanese mobile phones.

The user agent switcher can be found here:

http://chrispederick.com/work/user-agent-switcher/

Here is a list of Japanese user agents can be found here (need to be added in the plugin’s preferences):

http://www.zytrax.com/tech/web/mobile_ids.html#domoco

Marco thank you for the information!