It's a PS3 exclusive published by Square Enix over there
I thought the console version of Diablo III was quite good, and Square Enix thinks it's good enough to publish in Japan. The game will be a PS3 exclusive over there, and is set to launch on January 30th, 2014.
Until then, Japanese gamers can grab a demo starting this week that shows off a tiny slice of the game -- allowing you to play as the Wizard and Barbarian. The rest of us are just waiting for Reaper of Souls, the expansion that's set to drop in March 2014.
Try Square Enix’s Version Of Diablo III [Siliconera]