D Minor Ninth chord (Dm9) on the guitar fretboard
The D Minor Ninth chord (Dm9) is made of D (the root), F (minor third), A (perfect fifth, optional), C (minor seventh) and E (major ninth). The fretboard shows every one of them across the neck in standard tuning (E A D G B E), and plays them back so you can hear the chord.
The minor ninth is a minor seventh with a ninth stacked above, and the fifth is optional. Its notes repeat in several overlapping shapes on the neck. It sits between the minor seventh and the minor eleventh.