SEOUL, DEC. 6 -- For Roh Tae Woo, an accomplished athlete and would-be president of South Korea, chairing the Seoul Olympics committee in 1983 was the ideal job, a close friend said recently.

"In those days, he really was at peace and comfortable," said Ahn Kyo Duck, a friend for more than 30 years. "In this job, I don't think he's so happy. . . . He doesn't really like these complicated jobs. . . . He basically doesn't like to fight."

Nonetheless, Roh -- retired general, one-time coup maker, right-hand man to current President Chun Doo Hwan -- is in a fight right now, seeking election Dec. 16 in South Korea's first direct presidential contest in 16 years.

Although he has been slipping in recent polls, he is given a reasonable chance of pulling off what a year ago would have been unthinkable: emerging from the heart of what is probably the least popular regime in South Korea's history and winning a reasonably fair election. To do so, he must convince voters that he is a true believer in democracy, and not just a more personable version of the imperious and widely disliked Chun.

Perhaps even more important, Roh must show that he has the stature to bring this nation's military-dominated power structure with him into a new democratic age -- and, if it comes to that, to an acceptance of defeat.

Although he represents the ruling party, he is, at 55, the youngest and least known of the four major candidates. Voyaging from a secure middle-class family into the cocoon of the Korean Military Academy and a successful military career, and finally into the hands of the ruling party's public-relations experts, he has left few clues to his character in the public domain.

But close friends and longtime colleagues say the blandness of the resulting image is, in fact, close to reality. Roh is a genial man, they say, unemotive, patient, not a great thinker or strong leader but a seeker of harmony and consensus.

"I'm one of Mr. Roh's intimate friends, but it's very hard to explain his character because he has no special characteristics," said Ahn, who graduated from the military academy with Roh in 1955 and commanded the battalion next to his in Vietnam in 1969. In more than three decades, Ahn added, he has never seen Roh become angry.

The opposition scoffs at Roh's campaign slogan of being "an ordinary man."

"How can one who pointed guns at the people be a common man?" candidate Kim Young Sam asked at a rally yesterday.

Yet in many ways, friends say, the image is on target, in stark, though usually unspoken, contrast to Chun, another Korean Military Academy classmate.

"Chun has been a leader all his life," said an official who knows both men well and asked not to be identified. "He's a man who has great audacity. Roh would not have been the brightest in his class or even the best general," the official continued. "But he never would have missed a promotion. He's the kind of guy you'd never have anything against."In 1979, when President Park Chung Hee was assassinated, it was Chun, then a major general, who led a coup that blocked free elections. Roh, also a major general, was the willing accomplice.

For more than seven years, Roh played the role of loyal and patient number two, outwaiting those within the ruling camp who argued for a younger general or a civilian to succeed Chun.

"People thought he was sometimes very close to power, sometimes far from power," Ahn said. "But I could not find out from him. He never changed his face."

One senior official said that Roh remained close to Chun throughout and emerged as the least offensive candidate. Another said there was tension between the two men despite their long association.

"Maybe Mr. Chun thinks he's a little too soft, a little too indecisive," the official said. "If there had been someone more qualified, probably Mr. Roh would not have been chosen."

When Chun finally anointed Roh at a party convention in June, Roh dutifully accepted his "historic mandate." But Chun's attempt to pick the next president touched off a wave of protests.

On June 29, Roh appeared in public as his own man for the first time, announcing on television that he was prepared to face the opposition in a free election. Officials said he had cleared the outlines of the speech with Chun, who endorsed the startling about-face two days later.

Those who know Roh said the June 29 declaration was in character, not because of a burning devotion to democracy but because he has always sought to smooth things over, to find a compromise that can please everyone.

Roh's popularity surged. But by August, as workers took advantage of liberalization with strike after strike, the power structure behind him wavered. Roh traveled to Washington to meet President Reagan, risking an anti-American backlash among some voters to win some breathing space at home, diplomats here believe.

"That was a feat of political legerdemain," a knowledgeable diplomat said, "because in the week before June 29, he was just about out -- and in the week before he was in the United States, he was just about out again. The hardliners were saying, 'Thank you very much, Mr. Democracy. This is what you've brought.' There was a lot of questioning."

Now Roh may be in trouble again, as the ruling party senses opposition candidates Kim Young Sam and Kim Dae Jung gaining ground. Roh and his handlers have responded by abandoning the image of the soft democrat. Instead, they are warning of chaos if the opposition wins and promising to crush radical leftist forces if elected.His father was a local official, and Roh aimed for a career as a doctor until the Korean war of 1950-1953 intervened.

"He had a very secure childhood, in a more worldly family than Chun's," one friend said. "He would have been exposed to the phonograph in the 1930s, that kind of thing. And he married into a family that joined the modern world two generations ago."

Graduating with the first four-year class of the Korean Military Academy, he was steeped in an honor code imported from the U.S. Military Academy at West Point and bonded to a group of soldiers that cohered through the 1979 coup and beyond. But Roh didn't have a "soldier's mentality," said Ahn, who retired as a colonel in 1973 and now heads the Agricultural and Fishery Marketing Corp.

As a general, Roh never carried a swagger stick, Ahn said, and as a minister he conducted business at round tables.

Another acquaintance recalls Roh emerging from the showers of a shabby Army clubhouse after a round of golf to find there were no towels.

"Any other general would have sent his aide out for towels, fast," the acquaintance said. "But when I walked in, he was just drying himself off with paper towels."

Roh appeared to have landed near the center of power in 1979 with no special vision for leading the nation. "I cannot say I wanted to become a politician," he said recently.

Indeed, those who knew him during his past seven years as home minister, sports minister, Olympics chairman and party leader said he seemed content with the policies of the Chun administration.

"When I first met him, he seemed to be a person who was very much under Chun Doo Hwan, he was reined in," one western diplomat said.

Since June, Roh has worked hard to galvanize the ruling Democratic Justice Party, trying to convince thousands of functionaries that, after 26 years of authoritarian rule, victory will not be handed to them this time. Reflecting the classic number two's dilemma, he also has distanced himself from Chun as much as he can without seeming disloyal.

The opposition dismisses Roh's criticism of Chun's regime -- of corruption, of high-handedness -- as a tactic, meaningless after their long years of comradeship. Some observers disagree.

"Roh has come a long way in the last 10 months," the diplomat said. "There's something a little more visionary there besides, 'We've got to deal with the commies.' "

Roh's chances improved when both opposition Kims decided to run, splitting the antigovernment forces. But Roh's harsh rhetoric of recent days has led some to question once again the ruling party's conversion to democracy.

"He really believes in democracy," his friend Ahn said. "But the people around him say it's never been that way before, and they still do not all believe that it can happen now."