Contest #1 - Figure out the chapter title reference (Patreon)

After hearing back from a patron about wanting an opportunity to have a chance to introduce or name a recuring character in a story (whichever story is their favorite). I came up with this contest.

Now obviously not all chapter names are pure gold but I was quite happy with the chapter name I came up with for the upcoming chapter in Harry Potter the Sorcerer Supreme. Chapter 12 is titled "Bishop to E3". And was wondering if anyone was able to guess the reference.

If you want a shot at getting to introduce a character (as long as it works with the story) or even just take the chance to make a guess. Message me with your guess and then the character you want to add (and the story).

Of course, you can always just post it as a comment on the post but then everyone can see the guesses.