Heinrich Koch completed his treatise in 1793, a pioneering work regarding the musical phrase as well as a sonata form description (lacking that term). Composition of Opus 18 began in 1798, a momentous project for several reasons in Beethoven's early career. Here, the theories expressed in Koch's Versuch are taken as an analytic springboard into a thorough analysis of the first movement of the quartet published no. 3, which was the first composed; additionally, nos. 1 and 6 are explored to a lesser degree. This study in phrase-analysis demonstrates significance in the fundamental ideas of Koch as applied to a masterwork of the turn of the 19th century.