Bud Powell

Hard bop is a mid‑1950s subgenre of jazz that extends bebop’s virtuosic improvisation while bringing back a more explicitly African‑American groove. It incorporates pronounced influences from blues, rhythm & blues, and gospel—especially evident in riff‑based heads, church‑like harmonic movements on piano, and earthy saxophone phrasing. Compared with bebop, hard bop favors stronger backbeat accents, more grounded bass lines, and memorable, soulful melodies, all while retaining fast, harmonically rich improvisation when desired. Typical ensembles are small groups (often quintets) with trumpet, tenor sax, piano, bass, and drums. The style’s hallmark is the blend of bop harmony and lines with blues/gospel feeling and a driving swing feel.

Bebop is a modern jazz style characterized by fast tempos, intricate melodies, and harmonically advanced improvisation. It moved jazz from dance-oriented big-band music to art-focused small-ensemble performance, prioritizing virtuosity and spontaneous creativity. Typical bebop groups are quintets or quartets featuring trumpet, alto or tenor saxophone, piano, double bass, and drums. The music emphasizes asymmetrical phrasing, extended chords and substitutions, and contrafacts—new melodies written over the chord changes of popular songs. Rhythm sections center time on the ride cymbal, with the bass walking and the drummer "dropping bombs" on snare and bass drum. Melodies are angular and chromatic, and soloists outline rapidly shifting harmonies with bebop scales, enclosure tones, and altered dominants.

Cool jazz is a modern jazz style marked by relaxed tempos, lighter tone, and a focus on arrangement, counterpoint, and timbral clarity. It favors understatement over virtuoso display and uses dynamics, space, and balance to create an airy, "cool" ambience. Emerging in the late 1940s, the style drew on bebop’s harmonic sophistication while smoothing its angular edges, often incorporating classical techniques such as linear writing and orchestral color. Hallmarks include brushed drums, lyrical improvisation, careful voice-leading, and unusual instrumentation (for jazz) like French horn and tuba alongside trumpet, saxophones, trombone, piano, bass, and drums. Although associated with the U.S. West Coast in the 1950s, cool jazz originated in New York through sessions led by Miles Davis and arranged by Gil Evans and others. It went on to influence bossa nova, third stream, modal jazz, and later smooth jazz and lounge aesthetics.

Jazz is an improvisation-centered music tradition that emerged from African American communities in the early 20th century. It blends blues feeling, ragtime syncopation, European harmonic practice, and brass band instrumentation into a flexible, conversational art. Defining features include swing rhythm (a triplet-based pulse), call-and-response phrasing, blue notes, and extended harmonies built on 7ths, 9ths, 11ths, and 13ths. Jazz is as much a way of making music—spontaneous interaction, variation, and personal sound—as it is a set of forms and tunes. Across its history, jazz has continually hybridized, from New Orleans ensembles and big-band swing to bebop, cool and hard bop, modal and free jazz, fusion, and contemporary cross-genre experiments. Its influence permeates global popular and art music.

Stride (often called Harlem stride piano) is an early jazz piano style distinguished by a powerful, syncopated left hand that "strides" between low bass notes or octaves on beats 1 and 3 and mid‑range chords on beats 2 and 4, while the right hand plays a highly embellished melody, runs, and improvised variations. Emerging in New York City—especially Harlem—after ragtime, stride expanded the rhythmic looseness, harmonic richness, and improvisational freedom that would feed directly into swing and later jazz piano traditions. It is both virtuosic and danceable, equally suited to fast showpieces and tender ballads, and was central to piano "cutting contests" of the era.

Ragtime is an African American–rooted piano style that flourished from the 1890s to the 1910s, characterized by lively syncopation in the right hand against a steady, march-like “oom‑pah” accompaniment in the left hand. Typically written in 2/4 or 4/4 time and notated with straight (unswung) eighth notes, classic rags unfold in multiple 16‑bar strains, often in the form AABBACCDD. The music draws on cakewalk rhythms, marching-band forms, and popular song, and it became a sensation through sheet music, piano rolls, and parlor performance. Scott Joplin, known as the “King of Ragtime,” helped codify the genre’s refined, compositional approach, calling for moderate tempos and a clear, singing melody. Beyond solo piano, ragtime was arranged for small ensembles and orchestras, found a home in vaudeville and dance halls, and laid essential groundwork for early jazz, stride piano, and much of 20th‑century American popular music.