As chromaticism expanded in the long nineteenth century, composers sometimes relied upon the expedient of enharmonic spelling at the cost of indicating true chord function. In this foundational study of the rare case of ^♭IV, we focus on those examples where the voice leading suggests that we accept such striking chromaticism at the composer's word. From our analyses of Chopin's ^♭IV usages, we have derived three voice leading paradigms and will present examples of each, ranging from local surface progressions to the deepest layer of harmonic organization. They are: 1)I-^♭IV-V-I, 2) I-IV-^♭IV-I⁶ or (#)III#, and 3) ^♭IV as the chromatically altered upper third of ^♭II or II. Chopin appears to be a pioneer of all of these usages, often conjuring up ^♭IV in relationship with the more common lowerings, ^♭II and ^♭VI, an interdependent family of expressive inflections.

The larger conclusion we draw from this analysis is that some nineteenth-century chromaticism cannot be reduced to a diatonic background, but is indeed structurally chromatic. This view of irreducible chromaticism resonates with, rather than represses, the widely expanded expressive spectrum achieved in the Romantic period. It is offered as an amendment to Schenker's claim, still reaffirmed by prominent followers, that only diatonic tones can be found at the deepest structural level. We contend that the permeation of chromaticism like ^♭IV deep into tonal grammar was integral to the naturally expanding life of the tone and not merely the colorful adornment of an inflexible diatony.