Harlem Stride Piano, Stride Piano, or just Stride, is a jazz piano style that was developed in the large cities of the East Coast, mainly in the New York, during 1920s and 1930s. The left hand may play a four-beat pulse with a single bass note, octave, seventh or tenth interval on the first and third beats, and a chord on the second and fourth beats. Occasionally, this is reversed by placing the chord on the downbeat, for one or even several beats (but not by placing the chord in the bass). Unlike earlier "St. Louis" pianists, stride players' left hand often leapt greater distances on the keyboard, and they played faster and improvised. However, stride has always been played at slow tempos as well. Another major branch of early jazz piano that is mistaken for Harlem stride took root in New Orleans, where pianists were called "professors". Their style is arguably distant from the more dominant New York school, especially in the more simple right hand and regional repertoire. Jelly Roll Morton's sound is distinguished by his use of sixths in the left hand instead of single notes or tenths. This was part of what gave his playing its noted "New Orleans" flavor. (Wikipedia)