In fact the first title to be released by Yakuza creator Toshihiro Nagoshi's new studio is sci-fi shooter Binary Domain. Work on Yakuza 5 has only just started.
The next completed project from the new team will be Yakuza Black Panther 2 for PlayStation Portable, which is a spin-off sequel. They hope to attract even more newcomers to the series than the original - they were also surprised by the number of female gamers.
Development of Yakuza 5 is in the very early stages as SEGA has only just green lit the project, and so there's really no information to spill at this time. The last instalment in the series was Yakuza Of the End which featured a zombie apocalypse.