Blade for Barter (2005)

Blurb:
New Edo: A hodgepodge city-state where New York City meets ancient Japan, where skyscrapers tower over wooden shacks and salarymen and samurai walk side by side.

Enter Ryusuke Washington, a private samurai-for-hire, who along with his loyal dog Hachiko, must deal with the likes of the corrupt Samurai Union, the Mafuza, packs of dirty ronin who roam the streets, and the mad Lord Hoseki, who rules New Edo with bejeweled fingers and an iron fist!

Join Ryusuke--the last true samurai?--as he struggles to walk the straight and narrow path in a world gone topsy-turvy.

Source: www.anisearch.com/manga/6870