"City Hunter" was an anime that I did hear about from time to time and I did see a couple of episodes somewhere. My particular memory of that show involved the two strapping leads, Ryo Saeba and Kaori Makimura, and the running gag in the form of a 100-tonne mallet. I just read the summary of this 80s classic on Wikipedia and I'm wondering if I should give it another chance.
Definitely the first opening theme for "City Hunter" makes for a nice draw. "Ai yo Kienai de" (Don't Go Away, Love) was sung by Kahoru Kohiruimaki（小比類巻かほる）as her 5th single from May 1987, and it followed her breakthrough hit, "Hold On Me". There's something about the anison right from the percussive intro and into Kohhy's delivery that has me thinking that this was just as much a love call to Bubble Era Tokyo as it was an exciting theme song for the City Hunter detective team. I automatically think of night lights, West Shinjuku's mighty skyscrapers, and folks painting the town red. If anyone wants to get that "City Hunter" feeling, try walking through West Shinjuku at sunset or night.
"Ai yo Kienai de" managed to get as high as No. 8 on Oricon, and according to the comments I've read on YouTube, it looks like the song has become a beloved musical memory to many. Kohhy's good buddy Yoshiaki Ohuchi（大内義昭）was the composer with Keiko Aso（麻生圭子）providing the lyrics.
Many years later, the singer came up with an even more groovelicious version (although I miss the original intro). Kohhy is still looking pretty darn good in the video there.
P.S. Marcos V. took care of the ending theme for the anime, "Get Wild" by TM Network.