Stride (Piano)

Here the left hand is more sophisticated in how it accompanies the music. Rather than doing a walking bass-line, they would create interesting harmonies, almost playing its own melody.

See Oscar Peter explain what Stride is:

"The right hand is the instrument, the left hand is making the rhythm section out of work"

One part of this is that they started to extend their left-hands to include more spread-out notes in the LH, such as the 10th (which would later lead to chords like the 6/9 chord, and considering 11ths and whatnot).

It was said that Duke Ellington and His Orchestra was inspired by stride piano as it moved out of the 1920s.