Standard gypsy jazz bands are strictly acoustic ensembles, using mainly string instruments, including one or more guitars, a violin and a double bass. No drums or other percussion instruments are used; rhythm is provided by a steady "up-down" strumming technique known as the "pump" provided by one or two rhythm guitars. Violin, clarinet and lead guitar provide the melody and improvisational leads. Modern gypsy jazz bands often employ accordions and acoustic pianos as lead melodic instruments.
Reinhardt adapted his playing style to his own physical limitations---a severe burn suffered in a fire left two of the fingers of his left hand useless. Thus manouche rhythm guitarists use chords that employ two or three fingers, including major-sixth and minor-sixth intervals with added ninths. In contrast to conventional jazz harmonies, seventh chords are rarely used in rhythm accompaniment. The right wrist is positioned well above the instrument, with the wrist arched in a manner similar to classical guitar technique. The result is a precise, percussive strumming technique that is the hallmark of the manouche style.
Manouche melodies use minor scales with frequent chromatic (half-step) accents and intervals. Arpeggios play an important role in the improvisation, as do leading tones a half-step above and below and rapid glissandos up and down the fretboard. These were favorite techniques of Reinhardt's that require precise movements of the left hand. Scales often run through various the inversions of minor and diminished seventh chords, with diminished-seventh and dominant-seventh scales often combined and juxtaposed. The result is a bittersweet, major/minor sound that combines traditional gypsy harmony with complex jazz improvisational techniques.