A Hard Days Night Opening Chord 'Solved' | Page 2 | Fab Forum | The Beatles Bible

After looking on the forum, this chord was discussed in length.  Sorry for the extreme lateness in this post.  It’s old hat by now.

Suffice to say, it was a wonderful concoction.

My vote is the Dm11 sans 9th.  The important foundation note of D is where the chord must begin.

Since A Hard Day’s Night is in the key of G, the opening chord was designed to do 2 things:

a) establish a key foundation (Key of G),
b) create a sense of anticipation. 

So a “D” chord of some kind makes perfect sense (being the 5th in the key of G), which is precisely what was done. 
(For non-musicians, the 5th is the high point of a chord progression right before the verse comes back around from a chorus)

Whoever chose this particular chord had to be quite schooled in music theory, because the resulting chord is quite advanced. 
In musical terms, the chord is called a Dm11 sans 9th.  The D establishes key foundation, and the other notes in the chord provide
the suspense which I will articulate in a second.

The notes in a Dm11 are as follows, and they all serve a purpose.

D (root, provides key orientation)

F (third minor, sadness)

A (fifth – tonal support)

C (seventh – provides tension, bitterness, character)

E (ninth – provides extension and brightness)

G (11th – provides suspension, anticipation)

There is a LOT going on in this one chord, and was chosen for this effect.

Normally, it is difficult to play all these notes on one guitar (and the effect would not have been as good),
so it MADE SENSE to have different people play different parts so they, cumulatively, got the job done. 

GM asked George to play the F add 9 chord – F A C G
GM asked John to play a Dsus4 chord D A D G
GM asked Paul to simply play a D note.

I don’t hear the E note.  Making the chord a Dm11, no E.

The result was impressive… Confusion, anticipation, excitement.  A chord talked about for 50 years.