Yakuza 4 demo now available in Japan
March is Yakuza month. While Yakuza 3 is just barely releasing in North America and Europe on March 9th, Japan is eagerly awaiting for Yakuza 4 to come out on March 18th.
There is currently no word on Yakuza 4 releasing outside of Japan. The success of Yakuza 3 in the West will probably determine the fate of any localization possibilities.