City Hunter: 357 Magnum

City Hunter (シティーハンター, Shitī Hantā?) is a manga series written and illustrated by Tsukasa Hojo, published in Shueisha's Weekly Shōnen Jump from 1985 to 1991.

The series follows the exploits of Ryo Saeba, a "sweeper" who works to rid Tokyo of crime, and Kaori Makimura, a tomboyish girl who manages Ryo's business affairs. Their "City Hunter" business is an underground jack-of-all-trades operation, contacted by writing the letters "XYZ" on a blackboard at Shinjuku Station.

The manga was adapted into an animated television series by Sunrise Studios in 1987. The series lasted for 51 episodes, followed by two further seasons lasting a combined 114 episodes.

The City Hunter franchise spans four animated television series, three television specials, two original video animations, an animated feature film and a live-action Hong Kong film starring Jackie Chan. In 2001, Tsukasa Hojo started the Angel Heart, a City Hunter spin-off.

Source: Wikipedia