# F#9 How to decide if it is (f sharp dominant ninth) or (f dominant sharp ninth)?

How to decide if F#9 is f sharp dominant ninth chord or f dominant sharp ninth chord? Similarily for Gb9 also

Simple answer: Written as `F#9` it is most likely an F sharp chord with a ninth. An F chord with a sharp nine would probably be a dominant chord and be written as `F7#9`.

Elaboration: Thanks for the comments! So just as `F#13` is short for `F#7,13`, an `F#9` can indeed be short for `F#7,9`. In my practice, I have rarely seen it abbreviated like that – maybe because of the ambiguity you're asking about. So in theory, `F#9` can actually be both.

What do we do to disambiguate? Here are a few options:

1. If you mean a dominant chord with a sharp ninth, use `F7#9`. If you mean an F# chord with an added ninth, use `F#add9`.

2. You could also try to use space or parentheses to make things clear: `F# 9` and `F #9` or `F#(9)` and `F(#9)`.

3. In handwriting (or with superscript on a computer) you can make the meaning clearer by superscripting the options in smaller text.

I feel the least ambiguous solutions are `F7#9`/`F#add9` and `F(#9)`/`F#(9)`.

• By the way, F#9 typically means "F# seventh chord with major ninth". See jazzbooks.com/jazz/FQBK p. 15 for reference. Aug 4, 2020 at 14:38
• How would you write an F chord with a sharp nine, but without a seventh? But of course, nobody will actually encounter such a thing in real life, so F#9 means an F# 9. Aug 4, 2020 at 16:10
• @piiperiReinstateMonica I would write Fadd#9 to denote F A C G#, analogously to how Fadd9 means F A C G. Aug 4, 2020 at 22:42
• @user1079505 on what page of the Aebersold guide is the example? I don't see one with a plain `#9`. It's not totally complete or consistent, but the examples I see with altered ninths also include the `7` figure. Aug 5, 2020 at 14:51
• @MichaelCurtis p. 15 (printed number). I was referring to "X9" chord symbol. Indeed, normally #9 appears only in altered chords (which are dominant seventh chord). A chord that would contain #9, 3 and no 7 would be either something departing from functional harmony, or a strong suggestion for specific voicing – I have never met something like that in literature. A chord symbol would be Fadd#2 or Fadd#9, I believe. Aug 5, 2020 at 15:23

Just seeing F♯9, I'd play F♯, A♯, C♯, E and G♯, producing a dominant 9th on F♯.

Context usually helps, though, and the following chord would be a big clue. If it was B♭, then the chord in question would most likely be F7♯9.

Chord names will never occur isolated! Context would help like Tim says. The writing with the computer keys is F# 9 = Fsharp 9 or F #9 = F7 #9, but normally the printing of a notation program or professional layout should be F# (sharp=subscript)and 9 or F (#9=superscript). Everything else (as asking without context) is just confusing or fishing for reputation points ;)

I have not seen it written, but the "rule" seems to be don't omit 7 when extensions are altered.

So, in this questions the 7 is omitted, therefore the 9 isn't altered.

Accidentals are suffixed to the right of letters but prefixed to the left of numerals. That sets up the ambiguity and something needs to added - or superscript used - to delineate whether the accidental is a suffix or prefix.

Some examples with the numerals given in parenthesis. As you drop supposedly unnecessary numbers and parenthesis you eventually get the ambiguous `F#9` twice...

```F(7)(9)   => F(9)   => F9

F(7)(#9)  => F(#9)  => F#9

F#(7)(9)  => F#(9)  => F#9

F#(7)(#9) => F#(#9) => F##9
```

I suppose you could put back the parenthesis `F(#9)` but keeping the seventh `F7#9` seems clearer to indicate an altered chord. Otherwise assume the extension is not altered and the accidental applies to the letter.