The main subject in Chopin's Nocturne Op. 9 No. 1 consists of two phrases that each begin with "B A# G# F# D#". However, they are not aligned relative to the barline, because it seems that the first phrase is 3.5 bars (regardless of whether you consider the first four notes a pickup or not). I am quite surprised to find something like this in Chopin's music where [with the exception of improvisatory-type passages] phrases are usually demarcated by barlines; this kind of "stream of consciousness" that ignores the usual "4-bar phrase" seems more characteristic of Schumann. Does anyone know (or have references to) analysis of this particular part of this nocturne, or other similar examples in Chopin or his contemporaries?
What further baffles me is that when this exact subject returns, it is offset by half a bar relative to how the it appears the first time:
Thank you Richard for suggesting Rothstein's book. Below is a quote of what he writes about this nocturne.
The last two nocturnes, Op. 62 (1846), are considerably more complex—especially the first one in B Major, which is perhaps Chopin’s most breathtaking venture into endless melody. . . . I would point out the equivocal nature of the strong beats in Chopin’s 4/4 meter (the metrical shifts are reminiscent of 18th-century practice); I would also note that I interpret the cadence in m. 10 as a contraction or compression of a more leisurely close. The repeated F#’s sound like obvious expansions, given the motivic pattern. And there is clearly a phrase overlap in m. 7. Beyond this lie several mysteries, including the precise coordination of melody and harmony in the basic phrase . . . But these mysteries lie very close to the heart of Chopin’s late style, in which the rhythmic practices of a lifetime (however brief the lifetime!) reach a peak of complexity and refinement.