On the Tonic Added-Sixth Chord in Jazz

Abstract

This article investigates the major-mode tonic added-sixth chord in jazz, a characteristic harmony well established by the 1930s. Beginning around 1930, routine use of the tonic added-sixth chord established it as a “dialect” distinct from the triadic dialect of early jazz, ragtime, and the various styles and genres antecedent to jazz. The article begins with an examination of how ".fn_scaledegree(6)."/I can be understood as both “dependent” on ".fn_scaledegree(5)." and “independent” in both dialects. Examples from the literature then follow, with particular focus on transitional pieces, where the underlying tonics were triadic but independent ".fn_scaledegree(6)."/Is in the melody created de facto added-sixth chords. Such pieces exhibited a freer use of ".fn_scaledegree(6).", enabling it to function in tonic harmonies without depending on ".fn_scaledegree(5).". Once independent of ".fn_scaledegree(5).", ".fn_scaledegree(6)." was eventually treated as a chord tone routinely added to the triad without melodic impetus and establishing the added sixth as a standalone jazz chord. After presentation of a table that summarizes the functions of ".fn_scaledegree(6)."/I, the conclusion suggests a possible “inclusive” ".fn_scaledegree(6)." as a subcategory of the independent ".fn_scaledegree(6)." and then proceeds to issues regarding advancing ".fn_scaledegree(6)."/I, ".fn_scaledegree(5)."/I, or both to deeper structural levels and the relevance of tonic-triad types at such levels.