Was "Blackbird" Inspired by J. S. Bach's Bourrée in E Minor BWV 996?

Paul McCartney has cited Johann Sebastian Bach as an influence on "Blackbird". He admitted in 1997: "The original inspiration was from a well-known piece by Bach, which I never know the title of, which George and I had learned to play at early age; he better than me actually. Part of its structure is a particular harmonic thing between the meldoy and the bass line which intrigued me. Bach was always one of our favourite composers; we felt we had a lot in common with him. For some reason we thought this music was very similar to ours and we latched on to him amazingly quickly. We also liked the stories of him being the church organist and wopping this stuff out weekly, which was rather similar to what we were doing. We were very pleased to hear that. I developed the melody on guitar based on the Bach piece and took it somewhere else, took it to another level, then I just fitted the words to it." (Miles page 485)

Paul has forgotten the Bach piece's title, but many fans and scholars have assumed it's the Bourrée from his E Minor Lute Suite, BWV 996.

The only similarity I hear by listening is that they're both played on acoustic guitars. (But even then, the guitar Paul played on "Blackbird" had metal strings, whereas classical guitars typically use nylon strings to give a warmer sound - and the above recording is no exception).

Perhaps score study will yield results.

The Bourrée is in E minor while "Blackbird" is in G major - so they share the same key signature of one sharp - and both use highly chromatic harmony, but there is no clear relationship. This makes me wonder why so many have assumed the Bourrée to be the correct Bach piece. Might it be some other?

As it turns out, no, it is the Bourrée. Paul might not know the name of it, but he can still play it, and on 28 July 2005, Paul performed a live solo concert at Abbey Road Studios, which was recorded and released as Chaos and Creation at Abbey Road. During the performance, he again cited Bach as an influence on "Blackbird" and even played a few measures of the Bach original to illustrate the similarities (which can be heard from about 37:39-38:51 in the video below).

This proves that Paul was indeed thinking of the Bourrée in E minor when composing "Blackbird". However, Paul actually plays it wrong when demonstrating. He even acknowledges that the way he plays it, saying, "it really should go [sings it correctly], but we didn't know that bit." The version Paul played, then, is transcribed below (and transposed from D minor up to E minor for the sake of comparison).

Paul further admitted that "the bit where we went wrong, I later took that, the idea that you get the bass line and the top line (the melody) and turned it into 'Blackbird'." And now it makes sense! Comparing the Bourrée (as Paul played it) and "Blackbird" side by side, we can easily see the similarity. The example below shows in blue notes that are identical between the two, while red notes indicate comparable (if not identical) similarities. Further notice that Paul adds several notes (the black ones). 

And the rest of "Blackbird" uses similar harmonies - parallel tenths with a pedal G on the off beats. Those parallel tenths are only found in Paul's version of the Bourrée. Thus, Paul definitely was influenced by Bach's Bourrée in E minor  when writing "Blackbird", but by his own version of the Bourrée rather than the Bach original.


CITATIONS
Miles, Barry. Paul McCartney: Many Years From Now. Henry Holt and Company Inc., New York, NY 1997.