After 72 games in two matches, Anatoly Karpov and Gary Kasparov today managed to find an opening they had not used against each other before to begin their third world chess championship match.

But after 21 moves of a Gruenfeld defense, the 23-year-old champion and the 35-year-old challenger shook hands and agreed to a draw -- the 58th they have played in championship competition.

It was not a routine draw, however. The game was played cautiously by both sides partly because it began with an exchange of surprises. Kasparov, playing black, allowed a look of shock to appear on his face momentarily when Karpov -- usually inclined to open with the e-pawn -- advanced his d-pawn two squares instead. Two moves later, it was Karpov's turn to look surprised -- in fact, almost physically ill -- when Kasparov pushed his g-pawn rather than the more usual e-pawn. Karpov played the opening quite slowly; Kasparov made his first moves quickly, then slowed down.

The opening moves were played in a circuslike atmosphere, with photographers crowding around the stage, flashing bulbs and climbing on platforms and tables for unusual angles. Until the photographers were banished, about 10 minutes after play began, both players stuck to simple, well-known "book" lines of play. By the end (after about 3 1/2 hours in a game that could have gone for five), both players were approximately even in their time allotments and the position offered no significant advantage to either side.

Tickets for the game (ranging in price from $15 to $30) were sold out more than 2 1/2 hours before it began. "We sold more tickets than the room can take," match organizer Raymond Keene said before the game began.

Names of sponsors, including newspaper and book publishers, banks, British Airways, American Express and a London bookmaking agency, were prominently displayed on cards on the stage. The primary sponsor, Save and Prosper Ltd., had a placard directly in front of the playing table where it had to be seen by anyone watching the players. The stage was ringed with potted flowers, and a large bouquet stood behind the playing table.

For those who were unable to watch the game in the Park Lane Hotel's subbasement ballroom, the position and moves were instantly available on video screens in the lobby, in the press lounge and in an analysis room where grandmaster Nigel Short answered questions and provided a running commentary. Another commentary (with no questions asked) was provided on headphones for spectators in the ballroom. Video screens also were provided along the walls of the ballroom, activated by a special, electronically altered board and pieces that tracked each move as it was made.

The first game in a match that may run to 24 was essentially played for information-gathering purposes -- the players feeling out each other's strengths and weaknesses like prizefighters in a first round. Karpov may have picked a queen's pawn opening because of a curious fact about the last match: Of the eight won games, five were won by a player who opened with d4 and three were lost by a player who opened with e4. After the initial shock of Kasparov's response, Karpov was more probably trying to reach a solid position with slight advantages and no risk. The result of this game will give him an opportunity to prepare a more promising variation of this opening, if he chooses, for a future game.

The opening moves are always a small psychological battle until all the fresh ammunition -- surprise moves -- is exhausted. This happened around Move 12 today when Karpov offered a queen exchange. He still held a slight edge, but four moves later Kasparov completely neutralized the advantage and after a few more pieces were exchanged it became obvious that the game would be a draw.

In a similar situation in his first championship game against Boris Spassky, Bobby Fischer tried to avoid a draw with a wild gamble endangering his bishop. That game ended in a loss for Fischer, but years later analysts were still wondering whether Fischer's "madness" might have been a stroke of genius had there been a slight variation in the order of moves. Karpov and Kasparov, true to the Russian school of chess, which minimizes uncertainties, stayed within the borderlines of sanity.

"It was a pretty miserable game; sorry about that," commentator Short told a room full of chess fans as they watched the two players shake hands on the video screen.

The second game begins Wednesday.

Grandmaster Lubomir Kavalek contributed to this report.