This paper proposes a new category that refuses to choose between the labels rounded binary and ternary when a piece has some characteristics of both: an RBT, or Rounded Binary/Ternary form, has two clear sections, A and B, and has a return to the A section before the end, but does not have a two-reprise form, such pieces will be called "rounded binary" here), nor a B section ending in a secondary key other than V that is set off by strong sectional divisions, which, without a two-reprise form, will be called "ternary" here).
This study also examines pieces that may not "qualify" as RBT forms, but still have features that problematize their status as unambiguously ternary or rounded binary. Three such features include: 1. a tonally closed B section, in a key other than the dominant) within a two-reprise form, 2. the existence of a subordinate theme within the B section of a two-reprise form, and 3. a tonic-key PAC in the B section.
By using "RBT form" to describe those pieces with both rounded binary and ternary characteristics, analysts avoid having to dismiss some of what they see in such pieces, and at the same time clarify what they mean by the traditional labels: rounded binary is reserved for two-reprise structures only, while ternary is reserved for those two-part forms with a B section that ends in a secondary key.