City Hunter is a manga series created by Tsukasa Hojo that ran from 1985-1991, making it significantly older than most of the stuff posted here on HFG. The main character is Ryo Saeba, a private detective in Tokyo.
In Japan, City Hunter was a pretty popular series spawning multiple anime series, specials, and a movie. It also was turned into a movie starring Jackie Chan back in the 1990's and a new live-action movie is rumored to be in the works.
The manga and anime have been released in America but both are out of print.
Image Archive (.zip)