Measure 5 of the Moonlight Sonata Adagio Sostenuto is where the melody finally gets introduced.
But, only the first little bit, on beat 4. You can see this because the stems on the notes on measure 4 go in different directions.
To play it, you need to think that your right had has been divided in half and the thumb plays the lowest notes where your pinkie plays the highest notes at the same time.
Pay attention to beat one of measure 6 in the left. It has b sharps. It's a really common error to play either a b key or a c sharp key instead.
Measure 4 is where the Adagio movement of the Moonlight Sonata by Beethoven starts getting interesting.
It is also where the value of these videos starts to make sense.
There are 2 really common mistakes that people make when playing it. First, when there is a sharp in front of the "B" it is really confusing. Up until this point, for many students, all sharps are black keys. The idea of a sharp being a white key confuses students, even if they have been playing the piano for a while.
The second mistake, and it happens to experienced players as well, is forgetting that the sharps last until the end of the bar line, so both the B and the D remain B sharp and D sharp for beat 4.
As the harmony is less straightforward, it isn't as easy to catch a mistake in beat 4 of measure 4 as it would be in other places in this piece.
Have you ever had a student play a "B flat" when you asked him to play a "C flat?"
Or an "F sharp" instead of an "E sharp?"
Earlier this year I started making mini videos to help my online students (which is all of my students, at the moment) learn 5 note scales and root position triads for all of the keys.
The video series includes the enharmonic keys like F sharp/G flat. I ended up making 7 1-minute videos for the names of all the keys, including all of the black keys. No musical staff here. That comes later. People learn the names of their friends before they learn to spell them. Right?
The 7 minute mini course is free and you can find it here: