Why is the VII from the natural minor scale not called bVII?

Question

In my textbook there is a natural sign in front of the subtonic chord.

Why is the VII chord in minor called "natural" 7 with a natural sign in front and the diminished chord built on the raised 7 just called vii°? Shouldn't the natural VII chord from natural minor be called bVII since it is built on a minor 7th interval up from the tonic?

This chord also comes up in major so if it has the same name it makes more sense. Also, if you are going to call VII the natural one because it occurs in the natural minor scale then surely vii° should be called #vii°?

Answer 1

It's just a convention (as is all notation.) In minor keys, Roman numerals are based on the lowered form of the two mutable steps (6 and 7). This (at least in modern notational practice) makes the conventions for Roman numerals identical in major and minor keys; the roman numerals refer to a chord root that agrees with the key signature.

In some Renaissance and Baroque minor-key pieces, the key signature was different from that of the relative major. Usually, a flat signature minor key had one fewer flat but sometimes a sharp signature had one fewer sharp. The practice wasn't consistent.

Often, in analysis, some shortcuts are made for common occurrences. Kosta and Payne often use the harmonic minor as a basis for Roman numeral roots.

Answer 2

In natural minor scale notes, note ^7 is a full tone below the root. It gets sharpened when the harmonic or rising melodic comes out to play. Thus it will be called VII, in its 'standard' form. Everything uses the basic major scale notes as the datum point, so it makes sense that ^7 in the relative natural minor is called VII, not ♭VII - which could be construed as G♭ in key Am.

When we do talk about the raised leading note rooted chord in the minor key, then that gets called ♯VII - G♯ in key Am.And since it's then diminshed, it's actually ♯VII°.