All Indian classical music attempts to imitate the nuances of vocal music, and instruments are often judged by their ability to either sound like human vocal chords or perform the same intricate ornamentation associated with the voice. The commonest instrumental recitals often feature the best-known string instruments, sitar or sarod. But, in recent years the bansuri (bamboo flute) as well as the santoor – both formerly purely folk instruments – have made a tremendous contribution to the mainstream classical repertoire led by maestros Pandit Hariprasad Chaurasia and Pandit Shivkumar Sharma, respectively.

Unless it features a dhrupad-style instrument like the veena or surbahar (both often played unaccompanied by percussion), a classical instrumental recital typically features a solo instrument, accompanied by the drone of a tanpura, with percussion usually being provided by a tabla. Although jugalbandis (or duets between soloists of different instruments) tend to be enormously popular, they are a relatively recent phenomenon and still considered somewhat beyond the pale by some purists.

An instrumental recital is almost never accompanied by any kind of song, except in certain instances when the performer is playing in the gayaki-ang (literally 'singing-style' of playing) – the late sitar maestro Ustad Vilayat Khan being a case in point – and may outline a phrase or two of the composition using the voice, quickly followed by executing the same phrase on the instrument.

It is customary for the soloist to appear last on stage, after the accompanists have already taken their places - tabla usually to the left of the soloist, tanpura to the right - after which the final tuning begins. The soloist will begin the first piece with an alap, the first part of which involves exploring the individual notes of the chosen raag (melodic structure) in the lower octaves, gradually building up to the second section known as jor (literally to ‘join’) in which the improvisation continues – expanding to higher octaves and with a rhythmic pulse beginning to emerge.

As the pace gradually increases, some instrumentalists will add more rhythm, known as jhalla, by striking the drone strings of their instruments. Once this whole alap section is complete, the tabla accompaniment joins in for the first composition which, as with vocal music, is usually in a slow tempo although seldom as slow as the equivalent part of a vocal or khayal (Hindustani vocal) recital. The main function of the composition is to serve as a launch-pad from which the musician can segway into numerous improvisations of the same raag, but always returning to the main compositional phrase.

As with vocal music, a second, faster composition in the same raag will often follow, building up into a second jhalla, gathering more pace as it forms the finale of the raag. The second main item of the recital could either be a similar, though shorter execution of a different raag or, as is now the trend, a lighter item such as a folk tune, known as dhun, or even an instrumental version of a well-known thumri or bhajan.

Listen to the music | Pandit Prattyush Banerjee pushes the boundaries of the modern sarod, combining superb solo musicianship with innovations in composition and instrument design. Here he plays a jor and jhalla, live at Darbar Festival 2012.

Jameela Siddiqi is an author, linguist, and BBC cultural commentator, specialising in postcolonial fiction and the devotional music of South Asia.

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