Ninth Chords
Another chord type used in Rock, and more commonly in Jazz, is the ninth chord. The ninth chord is constructed from the major scale using the first (1), third (3), fifth (5), flattened seventh (b7) and ninth (9) notes of the scale. The ninth note is the same as the second note. The symbol for a ninth chord is the letter 9, placed after the letter name of the chord. Written next is the C ninth chord in root position.
C Ninth
Root Position
Because it is difficult to play all the notes of a ninth chord with on hand, it is acceptable to omit the root note of the ninth chord. This results in the following C9 shape.
Even though a note is missing, the chord still sounds like a ninth chord because the most important notes - the 3rd, b7th and the 9th are still present. Quite often the notes omitted by the right hand are played with the left hand, or vice versa.
Many extended chords can be simplified by omitting certain notes (usually the root or the 5th). E.g., it is common practice to omit the 5th when playing a seventh chord. This is also common practice when playing extended chord shapes.
