"I love to perform," says Ravi Shankar. "To me it is the greatest joy. You get an immediate response, which you don't get from a recording. I'm 83, I cannot run as fast as I could when I was 40 or 50, but I feel I'm a better musician. Indian music is not written-down, fixed music, so you enter deeper into it. You improvise and you discover new areas, new things."  Shankar is one of the greatest musicians of modern times, in any genre. Other musicians revere him; the late violinist Yehudi Menuhin compared his genius to that of Mozart. He became known in the 1960s through his friendship with George Harrison, and that association has since led to Indian classical music gaining a greater appreciation in the west. Now, kings and academies give Shankar medals, and a foundation in Delhi bearing his name is nearing completion. Yet this week he is back on the road, touring like a teenage rock artist.  At his side will be his successor: his 21-year-old daughter Anoushka. Like any king, Shankar wanted to create a dynasty: in his case, musical. So, nearly two decades ago, he had a small sitar built for his daughter Norah, then aged five. But events and family upheaval meant that it passed to his younger daughter from another relationship, Anoushka.  Anoushka is trying to honour her father's nebulous legacy while finding her own musical voice. Shankar's first daughter, Norah Jones, meanwhile, has moved on to the world of jazz and this year won five Grammys, catapulting herself to stardom, and her relationship with her dad into the gossip columns.  Both Shankars are open about their relationship with Norah. The Shankar daughters have played together in private: Anoushka on sitar, Norah on guitar. But, Anoushka says: "It sounded terrible; we haven't tried anything since then."  Shankar lost contact with Norah for eight years after her mother decided she did not want to see him. Those lost years are a source of regret for him. "Unfortunately, when she was 10, her mother wanted to be not found. Norah met me again when she was 18." He says Norah will not share in the inheritance of his Indian classical music legacy. "She's not at all into Indian music. The music she is famous for, what she has grown up with in America with her mother, is pure jazz and country-and-western music. She has heard me, that's all, she might be having this Indian music in her gene, but definitely she doesn't know at all, so there is no question of our trying to do anything."  Anoushka has performed with her father in public since the age of 13. She says that his music and live performances - despite his age and two heart attacks - are better than ever. "It's crazy with him. When you see him on stage he just changes instantly. You can see his age, he's frail and he can't hear very well and you have to help him up stairs, and you're very aware of him being an old, tired man. And then he gets on stage and instantly, instantly, once he starts playing, his face has this weird kind of glow to it where I just don't see the wrinkles any more. He's kind of on fire."  Shankar says performing with his daughter is one of his greatest joys: "She's one of the best disciples I have had. She's so remarkably talented and she inspires me a lot when she sits with me." But if Shankar gave life to his daughter's talent, there is a sense that Anoushka will need to have greater distance from her guru to thrive. Asked whether his daughter has a distinctive playing style, he says: "Not yet. Still, she's with me, under my influence, learning continuously. It's easier when you're apart from your guru."  Anoushka says differences are emerging: her sound is more feminine and there is a difference in tone. She is also into trance, and incorporates that into her experimental music. But the music father and daughter play together is very organic, and even on this tour, the sound that emerges may surprise them as much as the audience.  For Anoushka these will be the last performances for at least a year. "I need to get the pleasure back. Sometimes it just feels really tiring when we're touring all the time."  Part of Anoushka is rooted in the modernity of California, where she spent some of her childhood, and part of her in the ancient values of Indian classical music. The tensions from these different worlds are problematic, but also the making of her. She says that the key difference between herself and her father is the place and importance of performing Indian classical music in their respective lives. To him it is a banquet for the spirit and the senses; she needs nurturing from a wider world.  "Unlike my father, music is not my whole life," she says. "If he's performing every single day of his life, that will in itself sustain him, because he gets all of his passion and intensity out of music. I need to get it from my life to put it into my music. It's an output for me, it's not what sustains me. So I need friends, I need relationships, I need my cats, I need other arts, I need to travel, I need parties. All those things make me feel alive and passionate, and then I actually have something to give in my music."  Ravi says Anoushka will have a "duty" to get "the young generation more interested in Indian music". This clearly weighs on her mind: "There are the supporters who love my father's music so much that they see me as this kind of torch bearer and want me to carry on his legacy. That is one kind of pressure because they need me in some way to be a second him, which I find a bit ridiculous."  She continues to play and develop her talent because she loves "the intensity of it. I think I seek out intensity in everything, whether it's pleasure or pain. I just love to live in a very alive way, and in music in the same way, playing the sitar is one of those areas where I can reach certain depths of feeling which you don't come to too easily.  "And sometimes it's painful as well. Sometimes to have an aching melody makes me want to tear my heart out, it just aches and it hurts, but it's so beautiful. The joyous aspects of it, when we're all playing together, the harmony of it, everything just feels right."  · Ravi and Anoushka Shankar play the Cliffs Pavilion, Southend on Sea (01702 351135), tonight, then tour.
Ravi Shankar always knew his daughters would inherit his music. But he never expected one of them to become a jazz star. By Vikram Dodd.