The normally placid Democratic candidate for governor of Virginia, Lt. Gov. Charles S. Robb, took the offensive today in the first of six scheduled debates with his Republican opponent, state Attorney General J.

Supporters of Coleman, generally regarded as the better debater, had been savoring the joint appearance with Robb in Phi Beta Kappa Hall at the College of William and Mary here. But when the 90-minute exchange was over, not even the most ardent Coleman loyalist was willing to call the outcome better than a tie.

Robb began by thanking the sponsoring Virginia Retail Merchants Association for "the opportunity to clear up some misunderstandings" about his views. Then, turning squarely to his opponent, he added, "My good friend Marshall Coleman has said he has not always known where I stood."

Robb then clicked off his "for or against" position on 23 issues -- favoring, among other things, the state's right-to-work law; a cap on state employment; the death penalty; nuclear power and synfuels; a balanced budget and a state spending limitations; the Equal Rights Amendment and limited abortion funding, and opposing the Kemp-Roth tax cut.

"I'm sure I will offend everyone here with one of them, because many are controversial," he said.

Robb's recitation revealed nothing new to those who have followed his campaign, nor did it stake out positions vastly different from his opponent's. But his forceful, articulate performance had the effect of wowing the audience, and perhaps stunning Coleman, who was planning on overwhelming Robb with his rhetoric.

It also raised questions about whether Coleman might alter his debate approach before the two men meet again on June 27 for a confrontation to be broadcast on a stateside public television network.

"Marshall suffered from higher expectations and Robb benefited from lower expectations. They both did well," said David Blee, Coleman's press secretary, after today's meeting.

Robb's campaign manager, David Doak, was gleeful. "I think we won it. Chuck was crisp on the issues and he articulated well. He took command and held it. He looked gubernatorial."

Robb, who was accepting congratulations normally reserved for election night, said, "I feel good about it."

Coleman said only, "I'll let the experts decide" who won.

Doug Bailey, Coleman's media adviser said, "It was good for this early in the campaign. It's the best argument I can think of for many debates."

One spectator, Len Kraditor of the Virginia Speciality Stores of Newport News, said, "Last night I told my wife I was for Coleman, but now I'm not sure. There's no question Robb was the winner."

Kraditor said Coleman "hurt himself when he deferred to President Reagan on the draft."

Maureen Gallagher, a student at Virginia Commonwealth University, also mentioned Coleman's refusal to take a stand on the question of a peace-time draft. Robb said he favors it, and that it should never have been discontinued.

Gallagher declared Robb "definitely superior." She said she found the Democrat to be "more open" on several issues. As opposed to Robb's candor, she found Coleman to be "a PR man."

Coleman won the coin toss and got the first chance to speak to the bipartisan crowd of 350, promising to "follow the [Gov. John] Dalton example" by holding down spending and government regulation. He outlined his platform of "creative conservatism" that is closely tied to the success of the Reagan administration and promised that under no circumstances would a tax increase be enacted in his administration.

"It would be irresponsible not to make that pledge," Coleman said, adding that, "I pledge to veto more taxes if adopted" by the Democrat-controlled General Assembly.

Robb also said he is opposed to a tax increase, but added, "I won't prejudge the conservative legislature."

Fred Carter, a Williamsburg mortician, said he found Robb's "openmindedness" on the tax question in the tradition of "Jeffersonian leadership. You can't say you aren't going to spend more or hold taxes."

During the 40-minute question-and-answer session, Carter, who is black, said Coleman's support of Gov. John N. Dalton's veto of legislation to make Martin Luther King Jr.'s birthday a state holiday was "a slap in the face" to the many blacks who voted for Coleman four years ago. "If you did not intend to write off black support," asked Carter, why did you do that?"

Coleman said he realized that the legislation offered "important symbolism," and promised that, as governor, he would "not favor one group over another."

Robb jumped in, reminding Coleman that he had said he "wouldn't quarrel with the veto. I'm not sure where you do stand."

"I might have done otherwise if I were governor," replied Coleman, "but I am not a critic" of Dalton, who is one of his staunchest supporters.

Floyd Robertson Jr., a Lynchburg pharmacist who is a Coleman supporter, said he thought the debate was "about equal. But I was surprised to hear Robb say he was against unions and collective bargaining. I never thought I'd see a Democrat as conservative as him."

Robb did not come out against unions but, like Coleman, said he is opposed to collective bargaining by public employes.

In their quest for what both candidates perceive to be a highly conservative electorate, Coleman attempted to connect Robb with the policies of national Democratic leaders, including Robb's late father-in-law, former President Lyndon B. Johnson.

"In partnership with Ronald Reagan," Coleman said, he would work to "end the Great Society campaign against our tobacco farmers."

By indirection, Coleman also emphasized that, unlike Robb, who was born in Phoenix, Ariz., Coleman is "a product of Virginia schools," from elementary school in Waynesboro to the University of Virginia Law School. (Robb also is graduate of the law school at Charlottesville.)

Coleman's wit surfaced when he detected a loaded question asked of Robb by a woman identified as Margaret O'Bryan, who wanted him to tell "why it is so important to be able to work with the legislature," where Democrats hold a 3-to-1 majority.

After Robb gave the predictable answer, Coleman revealed that "the lady is the wife of Del. D. Wayne O'Bryan [D-Richmond]," and to her, he promised, "if your husband is reelected, I'll work with him."

Robb, carrying out the role of a humble victor, bolted across the stage and slapped Coleman on the back at the end of the debate.

Steve Ohina of Norfolk, like both Coleman and Robb a former Marine, may have summed up the show for many when he said that while he thought Robb "covered more ground, they're both good, nice-looking people."