spin off<<<<<<<<<
Kenzan was set well before any of the flag ship games and was a completely different experience, Rya Ga Gokotu 3 is more of the same and will do great.
If so BengaBenga then nothing shocking about that, series is nothing but a shooter now however you are probably mistaken with SF4.
Kenzan did 170k first week according to this site, Yakuza 3 will tear that number apart and SO4 barely beating that shows how big Yakuza actually is.