It's rach 3, of course.
It's funny, I had a similar brainstorm, but as of yet, I don't know how to post it.
When I was working in the theatre, during the stage rehearsals, when you're doing nothing more than actually playing, I played a game with one of the stage maestri. He was a pianist as well. It went like this: I played one note from the beginning of something. If he was lucky, he might have guessed it from that. More often then not, though, he couldn't. So I played the first two notes. actually, more than notes, it was the first two beats. Be they chords or single notes. And we'd go on, one note at a time, until he guessed the piece. And then he would do the same for me. I remember once, he played a d (below middle c) with the rh 3rd finger. And I guessed it!!!! Can you?
Topic: Name that tune!