See also: Parallel key and Parallel harmony.
Parallel and counter parallel chords are terms derived from the German (Parallelklang, Gegenparallelklang) to denote what is more often called in English the "relative", and possibly the "counter relative" chords. In Hugo Riemann's theory, and in German theory more generally, these chords share the function of the chord to which they link: subdominant parallel, dominant parallel, and tonic parallel.[1] Riemann defines the relation in terms of the movement of one single note:
For example, the major and and minor and .
| Major | Minor | |||||
| Parallel | Note letter in C | Name | Parallel | Note letter in C | Name | |
| Tp | A minor[2] | Submediant | tP | E major | Mediant | |
| Sp | D minor | Supertonic | sP | A major | Submediant | |
| Dp | E minor | Mediant | dP | B major | Subtonic | |
The tonic, subdominant, and dominant chords, in root position, each followed by its parallel. The parallel is formed by raising the fifth a whole tone.
The minor tonic, subdominant, dominant, and their parallels, created by lowering the fifth (German)/root (US) a whole tone.
The parallel chord (but not the counter parallel chord) of a major chord will always be the minor chord whose root is a minor third down from the major chord's root, inversely the parallel chord of a minor chord will be the major chord whose root is a minor third up from the root of the minor chord. Thus, in a major key, where the dominant is a major chord, the dominant parallel will be the minor chord a minor third below the dominant. In a minor key, where the dominant may be a minor chord, the dominant parallel will be the major chord a minor third above the (minor) dominant.
The name "parallel chord" comes from the German musical theory, where "Paralleltonart" means not "parallel key" but "relative key", and "parallel key" is "Varianttonart".
The "counter parallel" or "contrast chord" is terminology used in German theory derived mainly from Hugo Riemann to refer to (US:) relative (German: parallel) diatonic functions and is abbreviated Tcp in major and tCp in minor (Tkp respectively tKp in Riemann's diction). The chord can be seen as the "tonic parallel reversed" and is in a major key the same chord as the dominant parallel (Dp) and in a minor key equal to the subdominant parallel (sP); yet, it has another function. According to Riemann the chord is derived through Leittonwechselklänge (German, literally: "leading-tone changing sounds"), sometimes called gegenklang or "contrast chord", abbreviated Tl in major and tL in minor,[2] or, in German literature, abbreviated Tg in major and tG in minor (standing for "Gegenklang" or "Gegenparallel"). If chords may be formed by raising (major) or lowering (minor) the fifth a whole step ["parallel" or relative chords], they may also be formed by lowering (major) or raising (minor) the root a half-step to wechsel, the leading tone or leitton.
| Major | Minor | |||||
| Contrast | Note letter in C | Name | Contrast | Note letter in C | Name | |
| Tl (Tcp) | E minor | Mediant | tL (tCp) | A major | Submediant | |
| Sl (Scp) | A minor | Submediant | sL (sCp) | D major | Neapolitan chord | |
| Dl (Dcp) | B minor | Leading-tone | dL (dCp) | E major | Mediant | |