I'm working on playing Moonlight Sonata on the Piano and I'm having trouble relating what I'm reading on the sheet music to what I'm finding around the web on how to play it.

Here's a picture of the sheet music I'm using:

4th Measure

Based on my understanding of how to read music:

piano keyboard note-name chart

I read the notes in the treble staff as:

G#/B#/F# G#/C#/E G#/C#/D# F#/B/D#

It didn't sound quite right to me so I started looking around and everything I've found so far says it's played:

G#/C/F# G#/C#/E G#/C#/D# F#/C/D#

So.. I'm guessing the "C"s are correct, but why do they look like "B"s on the sheet music?

(full disclosure: I have no prior musical experience, I'm self thought, so I may be missing something obvious here).

  • 1
    Note that it would be awkward to try to have both C natural and C sharp near each other in the same piece, especially when B sharp can be used instead of C natural. Since the key signature has a C sharp, it's clearer to notate that note with a B sharp instead of a C natural. Jun 14, 2016 at 14:32
  • @ToddWilcox Thanks, I guess that does make sense. Just gotta get used to this stuff I suppose. :)
    – Mike
    Jun 14, 2016 at 14:57

1 Answer 1


B# and C are basically the same note. They are called enharmonic tones.

In modern musical notation and tuning, an enharmonic equivalent is a note, interval, or key signature that is equivalent to some other note, interval, or key signature but "spelled", or named differently.

The one note differs from the other depending on the harmony of the song. This specific piece you provided is in C# minor. So, the leading tone of this song is B# which leads to C#, as you can see in your piece.

So, while you play this piece on the piano, you'll be playing the B# as a natural C.

  • Wow, I feel dumb... I knew that.. I remember (now) that back when I was learning the notes that C=B# (no black key for "B" on the piano)... I guess I just got so caught up with trying to read the sheet music I just didn't correlate it correctly to the instrument itself. Thanks so much!
    – Mike
    Jun 14, 2016 at 14:55
  • FYI - While I'm fine with the edit to add the theory tag, the way I wrote the notes (how I was reading them) was correct: F#/B/D# The second "B" had no sharp next to it, so I was reading it as a "B". How would I know that the Sharp should have carried over to the second B?
    – Mike
    Jun 14, 2016 at 15:05
  • 4
    @Mike - any accidental in a bar affects all subsequent same notes. The following barline cancels all accidentals.
    – Tim
    Jun 14, 2016 at 16:17
  • 1
    @Mike exactly like tim said. The second B in that bar is still B# Jun 14, 2016 at 17:45
  • 3
    @Mike "The following barline cancels all accidentals" - just to add a comment to that: the reason why there is a sharp written against the D in bar 4, when D# is already in the key signature, is because bar 3 contained a D natural. Strictly speaking the D# in bar 4 is unnecessary, but it's a reminder not to play another D natural. You will hardly ever see a reminder about an accidental earlier in the same bar, though, like the "missing B sharp" in your question.
    – user19146
    Jun 15, 2016 at 0:23

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