F9b5

F9b5 is F, A, Cb, Eb and G, a nine flat five. The shape this page opens on is written 101001, lowest string first.

Also written F9(b5), F9-5 or F9♭5. The same chord either way; which spelling you meet depends on who wrote the chart.

There are 7 common shapes for F9b5 on the guitar, and 26 derived voicings in 3 families.

The common shapes, written lowest string first: 101001, 1212x3, x23243, x87887, x-8-9-0-10-11, 13-12-13-0-0-13, 13-12-13-12-12-13.

Shell. Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top. F9b5 has 1010xx, xx3243, x8788x, 13-12-13-12-x-x, 1x120x, 1014xx, x-8-x-8-10-7, 13-x-13-14-12-x.

Rootless. The root left to the bass player. Frees a finger for a tension. F9b5 has xx1203, x0100x, xx5445, xx7887, x-10-9-8-10-x, x-12-13-12-12-x, x2x243, x2524x.

Open string. An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful. F9b5 has 56000x, x6700x.

Tensions. A shell of F9b5, root, third and seventh, leaves a string free, and the tones that belong over it are the b13 (Db) and the 13 (D).

The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.