Tonstufen

Tonstufen are the individual degrees of a musical scale, counted from the tonic as Stufe I up to Stufe VII in diatonic systems. They describe the vertical pitch positions that form the scale, and they serve as the basis for analyzing harmony and melody in tonal music. Each Tonstufe has characteristic interval relations to the tonic and often bears a conventional function within a key.

In a major scale, the seven Tonstufen are I (tonika), II (supertonika), III (mediante), IV (subdominante), V (dominante), VI (submediant), and VII (leading tone). Triads built on these degrees typically have the pattern: I, IV and V are major; II, III and VI are minor; VII is diminished. In natural minor, the corresponding Tonstufen are i, ii°, III, iv, v, VI, VII, with different chord qualities. In harmonic and melodic minor, the seventh degree alters some chords (for example, V often becomes major, and VII can be major in the melodic minor ascending).

Tonstufen are central to roman-numeral analysis, where each degree signs the harmonic function: tonika (I, vi in minor contexts), subdominante (IV, II in some progressions), dominance (V). They also appear in solmization systems (Do Re Mi Fa Sol La Ti) and provide a framework for voice leading and modulation.

Beyond the common major and natural minor, the concept applies in other diatonic modes and in pedagogy to explain scale structure, tonal function, and harmonic relationships.