Is there any Relation between Fushigi Yuugi or Fushigi Yuugi Genbu Kaiden?

Well, im just reading the manga Fushigi Yuugi Genbu Kaiden and noticed that theres Fushigi Yuugi as well. Is there some sort of relation between the two, and if so, which should i read first?|||Genbu Kaiden is what happens before Fushigi Yuugi but you can read them in any oder. They are stories that can stand alone. Also they are by the same author. I like Genbu Kaiden better but they are both good.|||According to Wikipedia, Fushigi Yuugi Genbu Kaiden is a prequel to Fushigi Yuugi. Usually, it's best to just read manga like this in the order it was written, so I would suggest reading Fushigi Yuugi first.