How long is the longest running anime series? I know that the Pokemon anime has over 800 episodes, and One Piece has 600+ episodes, but I've heard that they are not in the top 10 of anime with the most number of episodes.

So what anime is longest?
Sazae-san (still ongoing) holds the Guinness World Record for the longest running animated television series at more than 7071 episodes. For a list of runner-ups, check this list.