I was looking at the sheet music for purple haze by Jimi Hendrix and I was pretty confused.

The first two bars, and all over the song, has a LOT of accidentals. Then the root of the first chord was also an accidental. I just couldn't figure out why the song was determined to be in the key that the sheet music states it is.

How is it determined that the tonal center is derived/fits from this key?

  • 1
    Purple Haze begins with a few tritones, which are weird and live in a key known only to Jimi :) But more seriously, I don't have the music but the key is probably based on the harmonies that exist once the verse itself starts.
    – Andy
    Jul 13, 2016 at 16:13
  • 3
    Whilst Jimi played it in E - a sort of amalgam of major and minor, by using his signature chord, E7#9, he often played on a guitar that was not at concert pitch. No digital tuners then. So possibly the recording transcribed came out in Eb, and the writer wanted to 'get it right'. Show us the dots, please!
    – Tim
    Jul 13, 2016 at 16:46
  • The soloing and riffing are mostly E pentatonic minor, so I would have transcribed it in E minor myself, and used accidentals for any chords "borrowed" from E major. It's definitely in E of some flavor. Jul 13, 2016 at 16:56
  • 1
    @JohnandLynHenry - I'm no lawyer, but I believe a snippet is ok. I've done that, properly credited, and no one yelled at me :) Jul 14, 2016 at 16:04

5 Answers 5


Basically, it's a shortcoming of traditional notation to be able to write down blues chords and such. I assume the notation is E major (4 sharps?)

Watching the video, a couple things are fairly clear.

  1. In the introduction, Jimi's exploiting the tritone, based on E, the tritone interval for which is B-flat. So there's one accidental for ya ... the bass would be playing Bb against his E.

  2. There are basically only 3 chords in the song, an E-type chord, a G-type chord, and an A-type chord. So the songs not so much in E major, but a minor-ish modal variation of E.

Since the G-Major chord doesn't technically "exist" in the key of E-Major ... you'll have accidentals every time it appears.

Keep in mind also that blues scales generally depart from both major and minor paradigms ... another opportunity for accidentals.

Finally, the E chord Jimi uses most of the time is the "Hendrix Chord", typically notated as E7#9. Wikipedia has some of that info in the entry for the song.

Hope this helps.


When the composer of a given piece of music is not the one to write up the sheet music, the key/time signature/etc. are up to the discretion of the transcriber. In some cases, they do a terrible job, leaving anyone looking at it confused or annoyed trying to read it as they chose to transcribe it. I suspect that some companies that publish this material use computer algorithms to analyze and transcribe but I don't have any evidence for that claim. When something is labeled "official", as you mentioned in a comment, you would really need to determine in what regard it is official. Jimi likely didn't sign off on it... It may just be indicating that it is released with the proper licensing.

From what I recall of this song, it wouldn't exactly be in a single key, ie, not all of the chords can be derived from a single tonal center/key. In particular, the E7 chord contains a #9, which cannot be derived from any naturally occurring any key.

  • We call it a 7#9, but it could be (and sometimes is) called dominant 7th with a minor 3 added. Thus it has been borrowed from the parallel minor key.
    – Tim
    Jul 15, 2016 at 6:45
  • @Tim - I can understand how and why it would be referred to that way, especially for those that don't understand the theory of extensions and alterations. I'm not so sure what you mean about borrowing from the parallel minor key, though. Do you mean that just the minor 3rd is borrowed? That's not how I typically see borrowing referred to, ie, not a single note added to a chord that is not borrowed. Jul 15, 2016 at 17:51
  • Borrowed is generally from the parallel key. As in E major, any chords/notes from E minor are also fair game. Not a theory rule, but seems to happen a lot
    – Tim
    Jul 15, 2016 at 19:53
  • @Tim - I won't say that it's wrong, just not how I've seen the term used. Ultimately, regardless of what the established theory says, if it makes sense and conveys the intended meaning to the player, I think of it as correct. Unless of course it is for a theory exam, then you're kind of stuck calling things based on the established theory. Jul 15, 2016 at 20:27
  • You can perfectly well notate a tune which is in Emin with 2 sharps key signature if you want to (because that suits the mode used). After all sometimes music with lots of modulations is notated with Cmaj key signature, just using accidentals throughout. That doesn't mean it is in Cmaj. The key signature is just a convenience, the key of the song is determined by melody and harmony.
    – danmcb
    Oct 5, 2019 at 16:34

Lets keep it simple and forget the fact its tuned down half a step.

The song is a II IV V progression. with the II chord acting as a kind of tritone substitution / secondary dominant chords. The song, however, is E Dorain, hence the Em7#9 chord is the prominent chord. E Dorain is especially prominent in the solo and he also uses the tritone as a passing note in the solo. Blues often used Dorain modes to solo, its a very blues mode with more of a Major feel than the straight up minor blues scale.

To expand on the beauty of music and how it flows in and out of itself the Em7#9 is simply a common tritone substitution or secondary dominant chord, something extremely common to Jazz and often used to switch keys. The tritone of D maj is A flat. A tritone wants to resolve either up or down the scale tone chords so either to the IV, V of a Key, in this case G major. From here Jazz musicans could then use G major as the root, effectively, switching down the circle of fifths, or the A if resolved to the V... or carry on in the same key, which is what Jimi does. This is what gives the tune such a bizarre feel with that Em7#9 chord acting as the prominent chord yet having such an un "root chord" feeling. - yet when the G Maj and A Maj hit it feels so resolved yet a tiny bit unfinished like the more proper i, IV V progression

This is why once Jimi has played the Em7#9 he plays the G maj then A Maj and it sounds so reliving to the ear. If it were in the Key of E minor / G Maj as most think then why is there an A Maj chord right? (this confused me for a long time before i learnt theory and jazz harmony and was told by a teacher to always try and find the common ionian or major scale of the piece of music) So the way i interpret is: D Maj, playing from the dorian mode E, with the G maj and A maj as the IV and V chords respectively.

The same tritone note is used during his solo, which sounds so bizare yet in key - this is the beauty of jazz and tritone substitutions

  • 1
    Saying "it's in E Dorian" might be justified, but "it's in D" definitely not. What do you think will happen if you tell someone "let's play Purple Haze in D"? Oct 5, 2019 at 11:52
  • Your right, i was emphasising the D in respects to the Dorian scale with the tritone note so it makes more sense, it is obviously dominated by E. Tho Thinking in just terms of E minor / G major throws the tritone and G and A chords off becasue there not in those scales. I will alter the comment
    – ryan boyce
    Oct 5, 2019 at 15:16
  • E Dorian and D major are the same scales, just different root notes, so it's perfectly justified to say it's in D major, because it is. E Dorian is not a key, it's a mode of the key of D major. He's correct, it's a II IV V in D major, aka the Dorian mode where the II is used as the root.
    – Ramon Leon
    Dec 20, 2022 at 23:00
  • this is nonsense. It's clearly a minor key, not in D maj. Sometimes you need to not get too hung up on modes and theory and just listen to where "home" obviously is.
    – danmcb
    Jan 3, 2023 at 6:27

(Disregarding the de-tuning of the guitar, and the deliberately dissonant intro ... )

Although the harmony (E/G/A - to me these chords sound like just root and fifth, I don't for instance hear a G# on the E chord, so that means all the notes are in E minor - referring to this performance) is pretty clearly E minor, the real giveaway is the melody, which so obviously wants to return to E. That first "Purple Haze ..." just sounds absolutely like a minor (blue) third, and at the end of the verse "Scuse me while I kiss the sky ..." sky lands slap bang on that E.

So it's E minor, all the way.

  • No, it's a II IV V in D major. Em G A, when you see two major chords a whole step apart, they're generally the IV and V; easy to figure out from there. This makes it's a Dorian mode progression, aka E Dorian in key of D.
    – Ramon Leon
    Dec 20, 2022 at 23:03

the key is in technically Bbmin because he tunes his guitar down a halfstep but it seems most people keep it in standard so for the sake of argument lets call it Bm. in the key of Bm, E technically would be a minor chord but he plays an E7, this works because he adds the #9 on top (which is just a minor 3rd up an octave) and does not play the 5 allowing it to act in the role of an Em7 which would typically have a minor 3rd (in this case a #9) and a diminished 5th (which isnt used). and the rest of the chords fall in the key of Bm/Dmaj. the G is the 4th, A is the 5th, Bm is the 6th and D is the root. You can make the argument you can improvise in the key of E when the E7#9 is playing but tbh I would advise something more like the E blues scale because of the minor 3rd and you would be able to play the minor 5th without consequence but in E Ionian, accidentally playing Gb and A would mess you up.

  • What is a 'minor fifth'?
    – Tim
    Dec 28, 2019 at 9:14

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