Gnawa music is anchored by the guembri (also called sintir), a three-string bass lute with a wooden body and a camel- or goatskin head. Its plucked low notes are dry and percussive, with a thud rather than a sustained ring. Iron castanets (qraqeb), held two per hand, supply a clattering metallic upper layer that fills any acoustic space. Vocals are call-and-response: a maâlem (master) calls and the group answers. A ceremony — a lila — typically begins at a relaxed pace and accelerates through the night.

The Gnawa community in Morocco descends from sub-Saharan West Africans brought north across the Sahara as slaves over centuries. The name 'Gnawa' is widely understood to be a corruption of 'Guinea'. The music's ritual frame (the lila) fuses West African spirit-possession ceremony with Moroccan Sufi Islam — each mluk (spirit) is associated with a color, a set of songs and specific guembri tunings, and a successful ceremony calls each spirit in sequence. In the 1960s and 1970s American jazz musicians, particularly the pianist Randy Weston, began collaborating with Gnawa masters in Tangier and Marrakech, opening the form to international listeners.

Start with the gimbri (also called hajhuj) — a three-stringed bass lute with a camel-skin resonator. The m'allem (master) plays melody and rhythm together, thumb and index finger striking a pattern called dqiqa. Above that, ensemble members clash iron castanets called qraqebs on a fast repeating figure. The base pulse is a 6/8 compound meter that Western ears hear as three-against-four polyrhythm. Then listen for the lila (all-night ritual) color-cycle: traditional lila covers seven mluk (spirit families), each keyed to a color — black (Saharan spirits), red (warrior blood), green (the Prophet), white (angels), blue (the sea and melancholy), yellow (female spirits, only women are possessed), and a final kaleidoscopic mix. Hamid El Kasri's 'Baba Mimoun' is a canonical white-cycle track; the low gimbri figure slowly rocks the body into trance. Festival recordings from Essaouira reveal the melodic vocabulary of the gimbri when it converses with visiting jazz players.

Enter through Maâlem Mahmoud Guinia's La Musique Sacrée des Gnawa (1990) — the reference recording of the traditional lila condensed for the studio. Then Hamid El Kasri's Fiyah (2010) for a contemporary top-tier m'allem. For the fusion axis, Randy Weston's Spirit! The Power of Music (2005) captures the jazz-piano-meets-gimbri conversation at its clearest. The Essaouira Gnaoua Festival's official live recordings show gnawa meeting outside music in real time. Play loud on a good speaker in a dim room; the gimbri wants physical air.

Gnawa is the descendant tradition of Black Africans brought to Morocco during the sub-Saharan slave trade from the 16th century onward; the name itself derives from 'Guinea.' Emancipated but socially excluded for centuries, the gnawa communities adopted Bilal — the first Black muezzin and companion of the Prophet Muhammad — as their spiritual ancestor from the 1960s onward, giving the tradition an Islamic-lineage self-identification. The pipeline into international jazz opened in 1969 when the American pianist Randy Weston moved to Tangier and began recording with Moroccan m'allems. The Essaouira Gnaoua Festival, held each June since 1998, draws over 300,000 people, most for free — one of Africa's largest music festivals and the single most important export vector for the tradition.