"Are you Russian?" one of the spectators asked the tall, distinguished looking, quiet man who had been watching the intense, complicated chess game between Anatoly Karpov and Washington master Eugene Meyer.

"I am not only Russian," replied the genial Anatolly Dobrynin, "I am Ambassador."

Ambassador or not, Dobrynin stood up for more than four hours while he watched world champion Karpov play 25 games simultaneously against local players, winning 21 1/2 of a possible 25 points. He stood not only because he was one of 170 spectators in a room of the Capital Hilton which had only 100 chairs, but because there is no satisfactory way to watch 25 simultaneous chess games while you are sitting dowm.

All of the seats in the hotel's Latin American Room were empty except for the 25 occupied by Karpov's opponents, who had paid $20 apiece for a chance to get a crack at the world champion - those and a few chairs on which enthusiastic fans who were not quite as tall as Dobrynin were standing to catch a glimpse of the board through the thick crowds surrounding some of the more interesting games.

Karpov had the best standing-room in the house - or rather, walking room, around the middle of a large hollow square of chess tables with the white sides of 25 boards facing toward him. Otherwise, the diminutive Russian, who was no taller than the shortest person in the room, would have had to stand on a chair, too, to see what was going on.

Karpov moves quickly, as you must if you are going to get through 25 games in a reasonable time. The first five moves (which were of course 125 moves for him) were played in two or three minutes, then he began slowing down at some of the boards, consider- ing a position for as long as 30 seconds before deciding what to do.

A neat, precise young man (looking a bit younger than his 26 years) dressed in a blue suit with a maroon tie, Karpov never seemed worried, surprised or hesitant except once or twice in the single game that he lost. Play began at 7 p.m., and all 25 games continued until 9:45, when some of the weaker players began to lose an a few of the stronger ones started setting for draws.The last game ended at 11:05, and Karpov showed no signs of fatigue, though he had certainly expended as much physical energy as most baseball players use during an average game and probably more mental energy than most accountants put into a full week's work.

A pitcher of ice water set out for him on a table in the center of the room stood untouched through th evening, but he did show one sign of human frailty about halfway through, sending out grandmaster Lubomir Kavalek (who had persuaded him to stop over in Washington on his way home from a trip to Caracas) to get him a glass of orange juice.

Before the event, it had been announced that no photographs would be permitted, but the fans and players brought in so many bootleg cameras that photos were allowed during the first five minutes of play.

Karpov remained unshakable, however, in his second condition - no press conference or interviews. So we will have to wait and see whether the rumors are true, that he will not defend his championship if it turns out that the challenger is the no. 1 bad man of Soviet chess, Victor Korchnoi, who defected in Holland 15 months ago and who has been mhamburg out of two Russian challengers in matches this year.

After the exhibition, having run up an impressive score of 19 victories, five draws and only one loss against some of the strongest players in the Washington area, Karpov affably authographed score sheets, books of his games and odd scraps of paper for the players and spectators. But in one case - that of Washington master Sam Greenlaw, who had inflicted the only defeat Karpov suffered - he had to be asked four times before he would sign the score sheet of his losing game. The champion accepts draws with equanimity, but hates to lose; he has lost only five games in tournament play since becoming champion three years ago.

Those lost to Karpov took it well, on the whole. "I tried a cheap shot," said Washington master Charles Powell with a self-deprecating grin. "It didn't work." Gustavo Gatti, president of the Inter-American Development Bank's staff association chess club, which sponsored the event, was more philosophical: "We played a very complicated game and I lost. I had a few hours of enjoyment, and that's what I wanted." For most of the participants, it was presumably worth the $20 fee to be able to tell their friends something like, "I lasted 32 moves against Karpov."

The five players who drew (Ken Clayton, Harvey Bernard, Robert Joynt and two brothers who are both masters, John and Eugene Meyer) seemed satisfied with the result, though some of them were busy analyzing how they might have won.

Greenlaw, the only victorious Washingtonian, explained his victory in simple though rather specialized terms: "He played the Botvinnik variation of the Anti-Meran Gambit (a variation of the Queen's Gambit) and he used the second-best middle-game continuation. I have played this opening about 10 times in tournaments and I have never lost with it, never drawn with it. When I saw that he was going to let me play this line, I began to feel very happy."

Part of Greenlaw's victory may be explained by the fact that Karpov had a few games on his mind at the same time, but by the time the world champion made his 15th move he would probably have a lost game on his hands even if this were the only game he was playing. Karpov's 12th move is the beginning of the "second-best" game-plan; 12. P-KN3 is preferable at this point and becomes essential in the next few moves.

When Karpov finally plays it, on move 24, it costs him a queen, and he could have resigned at this point. As in most chess games played at this level, the best combination is one that was not only played because both players saw its possibility. In the position shown in the diagram, if white plays 19. BxR, black can cut white to pieces: 19 . . .RxPch; 20. K-R1, RxBch; 21. K-N1, R-N7ch; 22. K-R1, R-QB7ch; 23. K-N1, RxQ. If this happened, Greenlaw remarked, "I probably would have taken the knight pawn before the queen, just to be mmean."