C#7b9

— About this chord

C#7b9 (C# dominant 7 flat 9) is a tense, altered dominant chord built from a diminished-7 shape stacked over the root, giving it a sharp, unresolved pull. A bebop and blues staple, it functions as a V7b9 resolving strongly to F# major or minor, adding chromatic bite to turnarounds and ii-V-I cadences. Movable diminished-based shapes make it easy to slide around the neck. Also searched as C#dom7b9, Db7b9, D♭7b9.