The final fingerpicking style to learn is the alternating thumb style. This style is particularly used in traditional Jazz styles such as Ragtime-Jazz and Dixieland Jazz. For this style the thumb alternates between two bass notes on each beat of the bar, usually beginning with the root bass note of the current chord.
The alternating bass lines shown below are for the C, F and G chords; i.e. the three principal chords in the key of G. The alternating bass line shown for the second F chord is for the root six major bar chord fingering.