That is, it *would* work (I can roam from home on it), but SoftBank refuses to sell or rent a SIM card, as far as I can tell.If obtaining a SIM is your only problem then be aware that Softbank has rental SIM cards. They are only available at the Narita Airport, Kansai International Airport, Nagoya / Central Japan Intl Airport, Fukuoka Airport, and New Chitose Airport branches.
http://www.softbank-rental.jp/en/phones/sim3g.php
That means that this phone would work here, except that in Japan, working with others is not important.
Hmm, but your phone will work here...