From the back cover:
In the port city of Nakamaru, the masks of deceit and treachery embroil the entire city. Plots and counterplots, loyalties, revenge...all can be found in this city of Wa.
You have been thrust amidst this cauldron of intrigue. You must pick your loyalties with care. Will you side with one of the yakuza gangs in their secret battle for control of the streets? Will you throw your fate into the political whirlwind that surrounds the powerful families of Nakamaru? Will you sohei battle his rivals for the hearts of the people?
Blood of the Yakuza is an adventure for use in your Oriental Adventures campaign. It includes a colorful map of Nakamaru and descriptions of the major NPCs, districts, and factions of the city. All of these make Nakamaru an exciting and dangerous place for adventure!