A prequel I never knew existed

Now here's something that's new to me. Apparently there is some sort of prequel to Hokuto no Ken, more commonly known as Fist of the North Star, called Fist of the Blue Sky. Thank goodness for Wikipedia! I actually find myself using Wikipedia to look up random tv shows and movies, and so far I've found about 3 anime series I have enjoyed, and one or two movies I also enjoyed, along with some good old campy stuff like Kids in the Hall Brain Candy

Fist of the Blue Sky (蒼天の拳, Sōten no Ken) is a prequel to the Tetsuo Hara and Buronson manga Fist of the North Star series. It is authored by Tetsuo Hara and Nobuhiko Horie supervised by Buronson.[1] The manga stars Kenshiro's predecessor (and Ryuken's older brother) Kasumi Kenshiro, the 62nd inheritor of Hokuto Shinken. Instead of a post-apocalyptic Mad Max-like landscape, the story takes place in an actual historical setting in the 1930s Shanghai, China during the Second Sino-Japanese war.

Beginning publication in 2001 and serialized in the Weekly Comic Bunch, the series reached its 16th volume tankōbon in publication in Japan on February 9, 2007. An animated version aired from October 4, 2006 to March 14, 2007. An English version of the manga was published by Gutsoon! Entertainment, serialized in the short-lived manga anthology Raijin Comics and collected into four volumes (along with an unpublished fifth volume) before Gutsoon folded. The license has yet to be picked up by another publisher.