Pyotr Ilyich Tchaikovsky · section 14 of 36

Chapter XII. The chord of the Ninth

Also in

Theory of HarmonyArnold Schoenberg · the ninth chordPractical Manual of HarmonyNikolai Rimsky-Korsakov · the ninth chordTreatise on HarmonyJean-Philippe Rameau · the ninth chord

§ 34. In major, as well as in minor we find on the 5-th degree a five— voiced chord: this is called the chord of the ninth, because of the interval of a ninth formed by the lowest voice and the uppermost voice.

This doubly - dissonant chord contains, in major, a major ninth, and is therefore called the major chord of the ninth. In minor it contains a minor ninth—and is called the minor chord of the ninth. The chord of the ninth resolves into the tonic triad; the intervals already discussed in the Dominant chord, are led as before; the ninth, however, progresses one degree downward—like the seventh.

In four-part-writing the fifth is omitted.

§ 35. The chord of the ninth, being a strongly dissonant chord, must be prepared; that is, the ninth must be part of the preceding chord, and must be kept in the same voice. The triads of the 2-nd, 4-th and 6-th degrees may serve as such preparing chords.

The tonic triad can also serve as preparing chord, if it appears in the same position as in the resolution of the chord of the ninth.

§ 36. Inversions of the chord of the ninth are not used.

Note. In figured Bass this chord is designated by 9.

*) The figures 8 7 denote that in the Dominant triad the octave should be led into the seventh, whereby the Dominant chord is formed