"Yer Blues" is clearly based on American blues: Robert Johnson, Muddy waters, Charlie Patton, Big Bill Broonzy, et cetera. But one way Lennon breaks with those models is through an extremely sophisticated rhythmic scheme. While Delta Blues performers very frequently play with rhythm (i.e. by holding a particular note a bit longer, or occasionally adding or dropping a beat), it always relaxes the rhythmic scheme. In contrast, when Lennon plays with rhythm in "Yer Blues", he increases the rhythmic sophistication.
For example, take 0:31-1:28, a transcription of which may be found below.
The music starts at the extremely slow tempo of dotted quarter = 52 beats per minute, which equates to eighth = 156 bpm. In the measure "Woo, Girl you know the reason", the subdivisions remain constant (156bpm), but the beat shifts from dotted eighth to quarter (quarter = 104). The following measure ("why") returns to the original tempo (dotted quarter = 52bpm), but only briefly because the subsequent three measures ("My mother was of the sky, My father was of the earth, But I am of the universe") doubles the tempo to 104bpm, retaining the sixteenth note subdivisions but again altering the beat from dotted quarter to dotted eighth. The tempo primo returns a measure before the next verse ("And you know what it's worth"). These types of metric modulations are entirely foreign to the American blues on which "Yer Blues" is based, and thus distinguishes the Beatles from its predecessors.
Paradoxically, while The White Album was the point at which the four Beatles firmly and clearly established individuality, the music on the album exhibits a greater sense of ensemble than any prior Beatles recordings - and the rhythmic sophistication of "Yer Blues" is a prime example.
This blog is a workshop for developing my analyses of The Beatles' music.