Introduction: a Taxonomic ProblemThese movements are so experimental [that] an accurate description [of them is] almost impossible. (Sachse 1958, p. 46; my translation) Schubert's early string quartets reveal a distinct tendency towards bi-or doublerotational designs combining elements of type 1 (lacking a development section) and type 2 sonata structures (off-tonic return of P material at the outset of the second rotation). Examples of the practice are found in first movements, slow movements and finales, and encompass at least nine movements from the ten quartets Schubert composed between 1810 and 1815, as shown in Table 1. The type 2 strategy of beginning the second rotation with P away from the tonic also features in movements from this period displaying more normative type 3 rhetoric (with a 'true' development section), such as the first movements of the quartets in D major, D. 94 and C major, D. 46, the former of which also features a compensatory return to P material in the tonic following the second rotation. 1 While the nine movements listed in Table 1 show a degree of differentiation in their treatment of the expositional repeat and the return to P material at the end of the movement (points I shall return to presently), they are unanimous in beginning the second rotation away from the tonic, but with clear P material. This particular strategy of an off-tonic second rotation in a birotational form is an acknowledged staple of Schubert's string-quartet sonatas during this period and has been understood in the context of the composer's fascination with the overture in this early stage of his career. 2 This tonal strategy, coupled with the lack of expositional repeat marks in some of these movements, led Martin Chusid to conclude that '[a] number of sonata form and bipartite movements in the chamber works of 1812 and 1813 point to another area of influence. These works […] do not have repeat indications after the exposition, an indication that Schubert may have been influenced by the formal organization of overtures where such repeats are normally omitted ' (1961, pp. 123-4).The weight of evidence for the influence of the overture is compelling. Schubert demonstrated something of an obsession with the form in his earliest years, writing four orchestral overtures (D. 4, D. 11, D. 12 and D. 26), the lost quartet overture, D. 20 and the Overture for String Quintet/Quartet, D. 8 (D. 8A), which is explicitly modelled on Cherubini's Faniska, all between