Hansen_Sebastian said: Shanghai is the name of the city in China. But if you're looking for the Touhou character, it's Shanghai Doll.
I know. Back in The Day, shanghai and hourai were the tags for the dolls. That was changed by using a mass edit to swap in the new *_doll tags. Something in the way Danbooru counts posts makes it really hate mass edits on common/popular tags, and if the tag is reused for something else it will go into a negative count. Apparently it's still there, even.