C#aug9

C#aug9 is C#, E#, A, B and D#, a augmented ninth. The shape this page opens on is written 121221, lowest string first.

Note by note. C# is the root, E# is the major third, A is the sharp fifth, B is the flat seventh and D# is the ninth.

Also written C#9#5, C#+9 or C#9(#5). The same chord either way; which spelling you meet depends on who wrote the chart.

There are 9 common shapes for C#aug9 on the guitar, and 18 derived voicings in 2 families.

One note away. Change a single note of C#aug9 and you have C#alt (with one note moved), C#aug7 (with one note taken away), C#9 (with one note moved) or C#9b5 (with one note moved).

The common shapes, written lowest string first: 121221, x43445, 767667, 98780x, 9-8-9-8-10-x, 9-12-9-10-0-11, 9-x-9-10-10-11, x-x-9-10-10-11, 13-14-13-14-14-13.

Under the hand. None of the shapes for C#aug9 uses an open string, so every one of them is movable; the lowest sits at the 1st fret. 4 of the 9 need a barre. Together they cover the neck from the 1st fret to the 14th.

Where it goes. C#aug9 is a dominant with its tension raised, so it still points at F# — harder than a plain seventh does, because the altered tones sit a semitone from where they are going.

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. C#aug9 has x4344x, 9898xx, x-x-11-10-12-11, x4x465, 9-x-9-10-10-x.

Rootless. The root left to the bass player. Frees a finger for a tension. C#aug9 has xx1201, x2324x, xx3445, xx7867, x-8-9-8-10-x, x-x-9-10-10-11, x-x-13-14-12-13, x2x241.

Tensions. A shell of C#aug9, root, third and seventh, leaves a string free, and the tones that belong over it are the #11 (F##).

What kind of chord this is. C#aug9 is an altered chord — a dominant seventh with its fifth or ninth moved. altered dominant chords on every root, and what they are for.

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