COTD 18: E11♭9

There are a few voicings that don't have simple tertian descriptions, and are easier to conceive of as "add" chords: just some note added onto a major or minor triad. Here's one:

B-13♭5, E11♭9, or D-(#11)
X8779X

Again, not exactly inspiring. However, in the right context it might be just what you need. When I get a moment, I'll play a true E11♭9 in an A minor progression and see how the ♭9 and 11 degrees interplay with the dominant tonality:

E11♭9
08779X

COTD 17: A9

Play "Rocket Man". I don't mean the whole song, just the bar where Sir Elton first sings the words "rocket man." This tab will help. OK, got it? Great. That's an A9 chord, and it contains probably the most important 9th voice in all pop music. The tune just doesn't sound right with just a normal A7. I tend to play standard voicings for the other chords in this song, and then this:

A9
X05600

I think it sounds perfect in this context. The two fretted notes are the guide tones. The open strings, low to high, are the root, ninth, and fifth. This means you can play the other three flavors of ninth chords with minimal effort:

AΔ9
X06600

A-9
X05500

A-Δ9
X06500

COTD 16: FΔ7

A close voicing has all of its notes constrained to an octave. Close voicings are not easy to play on the guitar generally because of its linear tuning. By contrast, the ukulele’s re-entrant fourth string makes close voicings very easy to play; it’s hard to play anything else.

If you find a close voicing that uses one open string, then you can find more inversions of that voicing in close form by just playing the inversions of the fretted notes and leaving the open string to ring out. Here’s an FΔ7 ("F major seven") close voicing that you may know:

XX3210

The fretted notes form the F major triad, and the open string is the seventh. Try playing that F major triad in its next inversion up:

XX7560

And the next up from that:

XX(10)(10)(10)(0)

And finally:

XX(15)(14)(13)(0)

These are all close voicings, with the open string ranging from the highest to the lowest voice. Here’s that same concept applied to C#-7

X4210X

X7660X

X(11)(11)(9)(0)X

X(16)(14)(13)(0)X

COTD 15: A-Δ9

This chord is from Chet Atkins' version of Walk, Don't Run, a tune you may not know the name of but will probably recognize if you google it.

A-Δ9
X(0)(10)(9)(9)(7)

It's a nice dramatic ending for this tune, originally written by Johnny Smith and made famous by the most successful instrumental band of all time: The Ventures.

COTD 14: The Hendrix/Gretty Chord

Sorry about the long pause. Perhaps it will soon be "Chord of the Fortnight."

D7#9
X5456X

This is used in the Beatles song Taxman, and as such should be referred to as the Gretty chord, after Jim Gretty, who worked at a music shop in Liverpool and taught the chord to the Beatles. Hendrix used this fingering often, and sometimes added a raised fifth:

E7#9#5
X76788

Both have their place, but good luck if you're hoping for other ergonomic voicings that are similarly bluesy without becoming too dissonant. Swapping out the root note for a 5th gives you this:

D7#9
X(9)(10)(10)(10)X

Which is an F#^oΔ7, and pretty ugly out of context. Note the spelling is exactly the same as D7#9. From low to high, these notes are F#, C, E#, A. The E# is because that note functions as a #9 in D7#9 and a Δ7 in F#^oΔ7. Neither of those degrees is an F note in their respective scale.

Here's a list  of D7#9's for you completists:

Substitution	Form	Root inversion	1st inv.	2nd inv.	3rd inv.	4th inv.*
Root	Close	X(17)(15)(11)(13)X	X8453X	N/A	X(9)(10)(7)(6)X	X(15)(12)(10)(7)X
Root	Drop-2	X5456X	X(9)(12)(10)(13)X	N/A	X(15)(15)(11)(15)X	X(8)(10)(7)(7)X
Root	Drop-3	(10)X(10)(10)(7)X	2X353X	N/A	8X476X	(13)X(12)(11)(13)X
5th	Close	N/A	X8421X	X9756X	X(12)(10)(10)(7)X	(15)(15)(11)(10)X
5th	Drop-2	N/A	X(9)(10)(10)(10)X	X(12)(15)(11)(13)X	X3426X	X8757X
5th	Drop-3	N/A	2X321X	5X456X	(8)X(7)(10)(7)	(13)X(10)(11)(10)X

* The 4^th inversion has the #9 in the lowest voice. In drop-2 and drop-3 voicings, this creates a ♭9 tension with the major 3^rd. Play the chords and see if you like them. Close forms are always constrained to an octave, making ♭9 intervals impossible. So they don't have that problem, but good luck playing them!

COTD 13: E♭7♭5 again (more of the Joe Pass ii-V-I)

Joe Pass recommended that you learn everything you know in all 12 keys. So I'll give the ii-V-I progression I've named for him in a few more forms, which you can move around the neck all you need in order to follow his advice. These will be named according to the "drop" form and inversion of that final major seventh chord. We already did the drop-3 root form, #2 on the list below. I've grouped them two at a time so that the highest note will be consistent within each pairing, and you can switch between drop-2 and drop-3 voicings while preserving the voice-leading in the top voice.

I hope Virgie likes the spooky colors!

Inversion	Drop form	ii (B♭-11)	V (E♭7♭5)	I (A♭Δ7)
1st	2	X4634X	X4524X	X3514X
Root	3	6X664X	5X564X	4X554X
2nd	2	X6869X	X6768X	X6658X
1st	3	9X889X	9X788X	8X688X
3rd	2	X(10)(12)(9)(11)X	X(10)(11)(8)(10)X	X(10)(10)(8)(9)X
2nd	3	(11)X(11)(13)(11)X	(11)X(11)(12)(10)X	(11)X(10)(12)(9)X
Root	2	X(13)(13)(13)(14)X	X(12)(13)(12)(14)X	X(11)(13)(12)(13)X
3rd	3	(16)X(13)(15)(14)X	(15)X(13)(14)(14)X	(15)X(13)(13)(13)X

Note that you're only seeing four distinct fingerings for the V chord, E♭7♭5. Like the rootless 13#9 chord, the dominant 7♭5 chord type, with the root, has tritone symmetry. So if you take one voicing and slide it up 6 frets, you get the same notes in a different order. The diminished 7th chord is the only other four-note chord with this property, but it is perfectly symmetric and repeats every three frets.