NEW YORK -- This afternoon on the observation platform of the World Trade Center, 107 stories above Manhattan, Garry Kasparov will face a new challenge to his decade-long chess dynasty in what he has called "perhaps the most difficult world championship match ever."

He might just be right.

The challenger, Viswanathan Anand, is six years younger than the 32-year-old Kasparov in a game in which years can take the same toll as in boxing or tennis. Anand has an extraordinary memory and one of the fastest minds in chess history. In his native India, he has inspired a surge of interest in chess much like the one Bobby Fischer started in the United States when he played for the world championship in 1972.