Editorial, guardian.co.uk

In 1997, at a concert to celebrate India's half-century of freedom from British rule, Amjad Ali Khan began with a small joke.

"Indian classical music has always been free," he quipped. "But it is a freedom within discipline – which is a beautiful concept." Undoubtedly one of India's greatest musicians, Khan is also exponent of a tradition that dates back to medieval times. His instrument is the sarod, a short-necked lute descended from the Afghan rabab. Its metal fingerboard has no frets, which makes it tough to play, and it is played with the rims of the fingernails. "A particular torture" is how it is described by Khan, who has to wear special plastic nails. It has been in Khan's family for six generations – "whoever is playing the sarod today learned directly or indirectly from my forefathers"; the story goes that when his father was asked by India's President whether he needed anything, he asked only for protection of raag Darbari Kanhra, which he felt was being abused by other performers. But Khan is no prisoner to tradition: he composes his own raags and seeks out western musicians for collaboration. His sons Amaan and Ayaan play the sarod too, and his description of their musical education captures some of the wonder of Hindustani classical: "When my sons came into the world, we sang the traditional song into their ears. As my father taught me to play – making me imitate on my sarod what he sang to me – so I did with my sons."