"Back and there again: The Vexing Problem with Prequels"

Vol. 1 of Shaman King by Hiroyuki Takai 

One of my favorite parts of the Manga Shaman King by Hiroyuki Takai is found in  volumes 19 and 20.  These two volumes take a break from the main plot (Yoh droping out of the Shaman tournament by order of Lady Jeanne in order to save Ren's life) to look at the background of Yoh and Anna's relationship.

What makes this story work is how it tries to provide background information without trying to ram down your throat the fact that it is before the main story, which is common problem among prequels and why I'm not a big fan of them.  I had this same problem with The Hobbit movies when they came out.  It's one thing to have references and little Easter eggs about but it shouldn't be the main focus.  The Hobbit is a separate story with only a few connections to Lord of the Rings.  Nobody cares about the stuff going on with the ring, in fact Jackson ruins the whole mystery of the ring by reveling that it is Saron's ring in The Hobbit  as it spoils the suprise of some silly old magic ring being something so powerful and dangerous (whether you saw Lord of the Rings or not).  The prequel break in Shaman King works because it is telling a separate story that has only a few connections to the main plot, which is what a prequel should be. 

Bibliography 

http://shamanking.wikia.com/wiki/Shaman_King