There once was a man named Mr. Braun. Not much was known about him, except for these things: he was married to a piano teacher, he was born and lived and married in Germany, and he had died a week earlier. Now, since he was dead and had no other living relatives, his estate would go to his wife (he left no will). The problem is, two women came forward, claiming to be the real Mrs. Braun.

Now, you're a detective, trying to figure out who is the real Mrs. Braun by having a piano competition. Mrs. Braun was an exceptional pianist, who could play many complex pieces. When you met them, they were sitting in a room with a couch and a piano. You extended your hand to greet them. One of them, a blonde, wore one ring (her wedding ring), which dug painfully into your hand when she shook it. The other (brunette) had one wedding ring also, but since it was on the other hand, you figured it was safe to shake.

Anyway, you put on the show with a lawyer as your witness. The blonde sat down and played Beethoven's Fifth with no trouble whatsoever, as did the brunette. They were both equal, but you managed to tell who the REAL Mrs. Braun was.

Who was it and how did you know?