A bandish is the compositional kernel of a Hindustani performance. After the alap has established the raag, the bandish enters — a brief composition, usually two lines (sthayi and antara), set to a specific raag in a specific taal. The text is in Braj Bhasha, Hindi, or sometimes Urdu, usually devotional or romantic, and the melody is fixed.
The bandish serves several functions. It announces the raag definitively. It establishes the taal cycle so the tabla player can enter. And critically, it gives the artist a melodic skeleton to return to between improvised passages. After every taan (fast melodic run), every tihai (rhythmic cadence), every avartan (taal cycle) of improvisation, the singer returns to a phrase of the bandish — and the tabla returns to sam at the same moment.
Bandishes are passed down within gharanas. Many are centuries old, attributed to specific composers (often poets writing under pen-names like Sadarang or Adarang). Each gharana has its own bandish repertoire, and the choice of bandish in a concert is often as informative about the artist's lineage as the choice of raag.
The sthayi-antara structure typically inhabits different octave ranges — the sthayi anchored in the middle, the antara reaching to the upper. The contrast between the two halves itself becomes material for elaboration.