The only rules with this are: The story must be behind an LJ cut and it must have a disclaimer on it. Other than that, have fun! Any Sagwa fan is welcome to try their hand at writing one!
An example of how one should look would be this:
Disc: Sagwa and all its characters belong to PBS and Amy Tan. I own anyone you don't recognize.
Title: Sagwa's New Friend
Summary: While in a faraway land after stowing away on a boat, Sagwa meets a new friend.