Difficult to define but very simple to identify when heard, bubbling is a style of rhythm guitar playing where the index finger is used to bar two or more strings on one fret while the remaining fingers are used to play other notes, usually in a triplet-like form, to enhance the chord. The thumb is sometimes used over the top of the neck to play a bass note. Bubbling is a style essentially invented and beat to shit by Jimi Hendrix, but can be heard in the work of Tom Johnston of the Doobie Brothers, Warren Haynes of the Allman Bros. and Govt. Mule, John Mayer, and many other players. Bubbling is a type of playing that bridges the gap between rhythm and lead.