This kid is a poster child for deliberate practice:

Marc Yu, a 9-year-old piano prodigy from Pasadena, Calif., recently played at a benefit for victims of the earthquake in Sichuan, China. And he didn't play "Row, Row, Row Your Boat." He played a piece that Chopin wrote for victims of the Polish-Russian war, the composer's "Nocturne in C Minor."

"My legs are long enough for the pedal, but still my legs aren't straight," Marc says. "I sometimes have to sit close...