Perhaps it is simply a coincidence, but I have just gone back and watched the scene in The Empire Strikes Back in which Luke goes into the cave on Dagobah and sees a vision of Darth Vader.

It comes at nearly the exact mid-point of that film, which is now the center of the nine episodes.

I have a private theory that this scene is one of the most important in the series, and is a key lens through which the entire story should be viewed.