dastgah

A dastgah is a musical modal system used in Persian traditional music. It provides the framework for composition, performance, and improvisation in Iranian classical music. While it shares a general idea with modal systems in other cultures, the dastgah has its own distinctive scales, melodic motions, and emotional colors that guide a performance.

A dastgah centers on a tonic pitch and a characteristic set of intervals that define its scale and mood. Performers explore short melodic units called gushehs, which together form a corpus associated with the dastgah. Improvisation within a dastgah follows traditional melodic rules and often moves through successive gushehs, returning to the tonic to close a phrase or piece. The system emphasizes microtonal steps and nuanced inflections that distinguish each mode.

There are several principal dastgahs, each with related sub-dastgahs or gushehs. Well-known examples include Shur, Segah, Rast, Chahargah, Mahur, and Homayun, among others. The exact inventory and naming can vary by tradition and school, but the general principle remains: a curated tonal center, a characteristic melodic palette, and a repertoire of motifs that define the mood of the mode.

Performance practice typically involves vocalists and instrumentalists such as tar, setar, santur, or ney. A performance often begins with an opening improvisation or introductory piece that establishes the chosen dastgah, after which the musician navigates through gushehs within the mode, sometimes modulating to related dastgahs. The system remains central to Iranian classical music and continues to influence contemporary composers and ensembles worldwide.