The World Chess Championship was set to open Monday with reigning champion Garry Kasparov defending with the black pieces against his challenger Anatoly Karpov.

Chief arbiter Geurt Gijssen of Holland late Sunday pulled out an envelope giving Kasparov the right to choose the colors for the opening game in the 24-game series.But the 27-year-old champion lost the advance of the first move when he plucked the wrong envelope from a black porcelain bowl at the opening ceremony at New York's Waldorf-Astoria Hotel.

The 38-year-old Karpov, who won the right to initiate play with the white pieces, broke into a wide grin.

"Tonight I'm going to get a good night's sleep," he told Reuters. "I need eight to nine hours."

Some 700 people attended the gala opening ceremony, which raised $200,000 for the American Chess Foundation Fund for Chess in School.

The challenger needs to score 12 1/2 points - champion Kasparov retaining the title in the event of a 12-12 tie.

Karpov has said he is confident he will regain the championship, but the chess world favors Kasparov, calling him the greatest player the sport has ever seen.

In the more than 120 games the two radically different men have played, most have ended in draws and Kasparov admits that he is champion only because he has beaten Karpov two times more than he has lost to him.