Does the flat (b) in bIII flatten all the notes?

Say we're talking about C major.

In C major the III is E major (a non-diatonic chord) which consists of the pitches: E G# B

If we do bIII, does that b mean I should flatten all the notes in the chord to: Eb G Bb. (?) Which would be an Eb major, the parallel minor's 3rd chord.

I've asked a new question for a better understanding of roman numerals.

The only thing the flat symbolizes is the root is lowered by a half step. So in C, a III would be built off of an E while the bIII would be built off of an Eb.

From there, you build the chord based on the type of chord written. For this example, since the bIII is uppercased with no addition symbols it's telling you the chord is major. So the chord would be Eb major spelled Eb, G, Bb.

I also highly recommend avoiding saying flatten all notes. In your example you can see where the confusion could step in as there is no flat on the G and flats do not cancel out sharps.

• Your last sentence is confusing (or wrong). What did you intend? Certainly if I'm playing a piece with key signature of Eb and I see a sharp sign in front of a written A, it means A# (even tho' the key sig is Ab) Commented Oct 25, 2018 at 14:27
• @CarlWitthoft fixed. I tried to do a quick answer this morning and screwed up the spelling. What I was trying to say is going from E (spelled E G# B) to Eb (spelled Eb G Bb), all notes are lowered, but putting a flat next to the G would be a mistake in this case since the flat does not cancel a sharp (like some people think).
– Dom
Commented Oct 25, 2018 at 14:56
• @Dom: When writing out music, one would e.g. raise a Bb by putting a natural sign in front of it, but if one were describing chords for purposes of performance, one would describe a chord with e.g. the pitches Eb-G-B as an `Eb(#5)` chord even though fifth is not a B#, but merely a B that isn't flatted. Commented Oct 25, 2018 at 17:10
• Although sharps and flats are added to the chord symbol, it's better to speak of it as raised or lowered tones. So not 'flatten notes' or 'cancel sharp', but simply 'lower tones.' Commented Jan 17, 2019 at 19:03
• @MichaelCurtis I completely agree.
– Dom
Commented Jan 17, 2019 at 19:48

Usually, when you see the bIII as a chord, you'd play a Eb major chord, so the notes would be Eb G Bb.

If you see biii, you'd play a Eb minor chord, which would be Eb Gb Bb (all the notes flat).

(notice the difference between the lower case i's and the Upper case ones; upper case refer to major chords, lower case to minor ones).

In quite a few sheet musics, this will be made clear. So, instead of bIII or biii, you'd see Eb or Ebm.

• Not 'usually'. Every time! Commented Oct 25, 2018 at 13:23
• @LaurencePayne Not all traditions have case-specific Roman numerals. Commented Jan 17, 2019 at 18:04

No, the flat (b) in bIII does not flatten all the notes in the chord, see here.

The flat (b) in bIII is to indicate that the root of the chord is flattened, i.e. the third note in C major (E) is flattened to Eb. The capital letters in III means that we are building a major chord. All in all, the notes that should be played are (Eb G Bb).

• I'm a little confused by your answer (even though I think you're correct). Your first line seems to suggest "yes, you do flatten all the notes," whereas your second line suggests you only lower the root. Could you clarify? Commented Jan 17, 2019 at 18:03
• You are absolulety right, sorry for that. I think I was answering the question before the edit. I adapted my answer to the edited question. Commented Jan 18, 2019 at 19:38