The overall form is 16+16, where the first 8 bars of each 16 are similar (ABA'C structure).

The main feature is a temporary modulation to the key III, which is 4 sharps sharper than the original key. It returns to the original key by changing the III to IIIx, and starting a circle of 4ths sequence.

2-5-1		circle of 4ths returning from IV
ii	V	I IV	iii VIx
			turnaround
ii V	ii V	I	VIx
2-5-1			251 to III
ii	V	I	#ivØ VIIx
		circle
IIIM	#ivm VIIx	IIIx	VIx
Repeat
		circle from bVIIx
		bVIIx	VIx
	251 to vi (rel minor)	circle of 4ths via IIx
ii	vii IIIx	vi	IIx
ii	V	I	I