A Slash Chord tells you which one of the notes within the chord will be the lowest tone that is played in that chord.
In the first examples C major is the slash chord. C major = C - E - G
C/C C the C note is the lowest tone in chord
This is a C major chord with C as the lowest tone
This is usually not indicated because it is assumed to be the lowest tone.
C/E the E note is the lowest tone in the chord
This is a C major first inversion
C/G the G note is the lowest tone in chord
This is a C major second inversion
C/B the B note is the lowest tone in chord
This is a C major seventh third inversion
C/D the D note is the lowest tone in chord
This is a C major ninth fourth
inversion
Now look at this
using the key of C# major:
C#/E# the E# note is the lowest tone in the chord
This is a C# major first inversion
C#/G# the G# note is the lowest tone in chord
This is a C# major second inversion
C#/B# the B note is the lowest tone in chord
This is a C# major seventh third inversion
C#/D# the D note is the lowest tone in chord
This is a C# major ninth fourth inversion
(Now do this for all other thirteen keys -
G, D, A, E, B, F# - Circle of Fifth's
F, Bb, E, Ab, Db, Gb, Cb - Circle of Fourths).
Now look at this using the key of C minor.
In the following examples C minor is the chord above the lowest tone. C minor = C -Eb- G
Cm/Eb the Eb note is the lowest tone in the chord
This is a C minor first inversion
Cm/G the G note is the lowest tone in chord
This is a C minor second inversion
Cm maj7/B the B note is the lowest tone in chord
This is a C minor major seventh third inversion
Cm/D the D note is the lowest tone in chord
This is a C minor ninth fourth
inversion
You can pick any note in a chord to be a slash chord. Many times this technique is used to move scale wise or chromaticly in the lowest tone:
"Stairway to Heaven" by Led Zeppelin:
Am/A - Am maj 7/G# - Am7/G - Bm7/F# - F maj 7 /F. This is a chromatic scale descending from A, G#, G, F#, F.
A is the root of A minor, G# is the major seventh of A minor, G is the flat seventh of A minor, F# is the fifth of Bm7, F is the root of Fmaj7.
"In Waltz For Debby" by Bill Evans & Gene Lees
A7/G - D7/F# - G7/F - C7/E - F7/Eb - Bb6/D - Gm7b5/Db - C7/C - C7/Bb - Am7/A.
Again a chromatic scale descending from G to A.
G is the flat seventh of A7, F# is the third of D7, F is the flat seventh of G7, E is the third of C7, Eb is the flat seventh of F7, D is the third of Bb6, Db is the flat fifth of Gm7b5, C is the root of C7, Br is the flat seventh of C7, A is the root of Am7.
Any chord can be made into a slash chord by simply adding whatever note after the slash sign.
