# Understanding V/ii♭9 Chord

I found this on Wikipedia.

The Bebop blues(Spitzer 2001, 62):

I7 IV7 I7 v7 I7 IV7 ♯IVo7 I7 V/ii♭9 ii7 V7 I7 V/ii♭9 ii7 V7

I can't parse the `V/ii♭9` chord symbol. What notes is this made up of?

V/ii denotes the (secondary) dominant (V) of the supertonic (ii).

In the key of C major this would refer to the (secondary) dominant of the supertonic Dm, which is an A major chord. Adding the b9 gives you A(add b9), but I suppose - especially since it is a jazz blues - a dominant 7 must be inferred and thus it is an A7(b9) chord, with the notes A, C#, E, G, Bb. (It is actually exemplified as A7(b9) in the wikipedia article although it is never stated that the example belongs to C major.) I believe that the correct notation should be V7(b9)/ii.

This is very reasonable since with the V/ii you'll find that you're dealing with standard turnarounds in the chord progression.

The whole chord progression in C becomes:

```| C7  | F7   | C7        | G7 C7  |
| F7  | F#º7 | C7        | A7(b9) |
| Dm7 | G7   | C7 A7(b9) | Dm7 G7 |
```

Another way of denoting this chord function would be VI7(b9). However since VI indicates a major chord which is not a member of the diatonic functions, it is instead traditionally analysed as a secondary dominant of the supertonic, i.e. V7(b9)/ii.

In traditional functional roman numeral analysis a slash is used to denote a harmonic function in relation to a diatonic note or chord. Note that this has nothing to do with slash chord notation!

• I thought about A, but why didn't the writer put VI, as this denotes Amaj (as opposed to min.)Yes, bog standard turnaround, written in a bizarre manner.
– Tim
Commented Oct 18, 2013 at 15:39
• could this be written VI7-9 ? The use of vi indicates minor, which is a given anyway.So it would be obvious that a major is played.Were the writer to need Fm (in C) he would write iv, wouldn't he ?
– Tim
Commented Oct 19, 2013 at 9:06
• The fourth measure should be Gm7 instead of G7. Commented Apr 5, 2020 at 22:12

Can't say I've come across it before, written that way, but, in C, it could be G7 with a flat 9. with a D bass, played D-G-B-D-F-Ab, but not necessarily in that order, except the D bass.The Ab should be an octave above the low G, otherwise there is a clash, and it wouldn't be a b9.

Love the term 'parse'!!

• Did you try playing it? Because to me it doesn't sound quite right... Commented Oct 18, 2013 at 14:28
• I believe your interpretation of the chord function is incorrect. However, a note regarding voicing of a b9 chord: you'd likely voice a b9 chord by (1) omitting the tonic [when a bass takes care of it], (2) voicing the b9 almost an octave below the tonic, or (3) have the b9 and the tonic note voiced next to each other (as long as they are not on top of your voicing). The diminished ninth voicing you suggest with the b9 an octave above the tonic is arguably the last dissonance still generally avoided in jazz voicing. :-) Commented Oct 18, 2013 at 14:37
• I normally do put the b9 at the bottom. However, the red herring of a slash chord precluded that happening, in my interpretation of the chord, thinking a 2 note was indicated at the bottom. If it's going to be called a b9, theoretically it goes up rather than down. Wouldn't that be a b2 ? Usually called b9 though...
– Tim
Commented Oct 18, 2013 at 15:53
• Can we call it a minor ninth, rather than diminished ninth ?
– Tim
Commented Oct 18, 2013 at 16:24
• Yes you are correct; minor ninth is the correct name! My error. (A diminished ninth I suppose would sound equivalent to an octave. :-) Commented Oct 20, 2013 at 21:11