slash chords

We kind of broached the subject of slash chords on the post concerning 6th chords. In that case we talked about one specific use of slash chords, viz. representing inversion, or that the chord in question's root is not the lowest, 'bass' note. That doesn't cover completely what slash chords do, so let's now generalize what a slash chord is:

A slash chord is a way of representing a harmonic structure that has a bass note which is other than the root of the chord indicated. A slash chord is written in the form X/Y (pronounced "X over Y") where X is some chord (usually a triad) and Y is to be understood as a single note: the bass note.

There are 2 broad categories of slash chords:

1. The bass note is a member of the chord in question (though not the root).
2. The bass note is not a note found in the chord in question.

Examples of (1) above: C/E is a C major triad with E as its lowest member (in classical terminology this is C major in first inversion). G/D represents G with its 5th as the lowest member ("second inversion"), and so on.

Examples of (2): A/Bb (Bb is not found in the A major triad), D/C, F#/F, E/C and so on...

Furthermore, in this category of slash chords there is at least one big subdivision. Take D/C: it can be seen as an inversion of a seventh chord (in this case D7 but with the 7th in the bass). But D/C may just indicate a C lydian situation, so let's note that context has everything to do with slash chords.

For instance, slash chords are a great way of indicating bass lines. Here's a common one:

C | G/B | Amin |

The bass here is a stepwise line descending (C - B - A).

Also slash chords are an easy way to indicate pedals. Take "Someday My Prince Will Come" four measures from the end (in the Real Book):

Bb/F | Cmin7/F F7 |

Obviously these 2 measures are an F pedal.