Arnold Schoenberg · section 38 of 44

Guidelines for the Use of the Diminished Seventh Chord

I. The diminished seventh chord can stand only where the degree whose ninth chord with omitted root it is could otherwise stand, and where its nondiatonic tones can move in accordance with their leading-tone direction. (This seems to contradict the freedom of movement otherwise granted to it, but that is not the case; it is only meant to draw attention to the fact that a different degree progression is present from the one the student assumes, if keeping to the leading-tone direction is impossible. For, for the time being, we allow ourselves enharmonic change only in the case of the connection discussed last: diminished seventh chord on the II [ninth chord] with the six-four chord of the first degree in major).

II. It can take the place of dominant or secondary-dominant seventh chords in all the functions of these chords, insofar as the chords that then follow it already lie, for us, within the key (see 141a). And for the time being this is also its most important function. In it it is of great value, since it softens many a harshness, especially where there is danger of a cross-relation and where turning points have not been observed. Particularly worth mentioning is the connection in musical example 140A under 3) at **), where, after the cadential six-four chord of the I degree, it brings about a continuation corresponding to the deceptive cadence and ending in the VI or IV. Further, the introduction of the same six-four chord shown in 141c, where it exercises its function as II degree. Both are very common turns.