Exploring J. S. Bach's musical thinking and performance intentions through the examination of his quaver-beam notation

Bach and his fellow musicians often beamed quavers beyond the beat-unit indicated by the time-signature. Two kinds of beaming were available: long (extended form, which is his norm) and short (default form, which he used less frequently). Normally both types were used in a piece; in many instances Bach’s use of the two beam types appears rational, being made for reasons of musical emphasis, often indicating the way the melodic lines were perceived, phrased or articulated. It is rare for Bach to use the short beam exclusively in a single movement; but when he did, his intentions appear to signal that it is an exceptional case of indicating the musical character (tempo) being outside of his normal range, i.e. either plodding mood (slow) or lively (fast).
There are also instances where Bach’s intentions behind his choice of the beam type are not very obvious. In a recently published article in Early Music (February 2016), I have argued that behind those instances of Bach’s ‘unintelligible’ choice were the conflicts of his interests and priorities in the music that resulted in a choice that contradicts the broader trend, or reveal the threshold of musical intensity when the density of musical activities forced Bach to switch his usual notational preference. More recent work jointly explored with Bach pianist, Daniel Martyn Lewis, suggested further possibilities of alluding greater varieties with finer nuance that reflect the spirit of Baroque performance practice.
Composers’ writing is sometimes indicative of how they felt an idea at the moment when writing it down. With an ultimate aim of spelling out the effect on Bach’s musical thinking and performance intentions, this paper attempts to seek further rational explanations for Bach’s choice of quaver beaming that guided him to explore the ideas he was engaged with.