WHEN SUTHICHAI YOON left Thailand last September and came to Harvard as a Nieman Fellow, the 32-year-old magazine editor of Bangkok's Nation Review had spent a decade playing a game with which few American journalists are even familiar--the game of controlled press.

In a nation where papers are regularly closed down and all other forms of media are government owned, Yoon and newspapermen like him tread a continual tightrope between their desire to maintain journalistic integrity and their need to avoid government wrath. It is a path which at times becomes exceedingly risky.

Sitting in the cushioned and carpeted library of the Nieman Foundation, surrounded by less restricted publications like The London Times and The Washington Post, Yoon recalls whispered threats, censored stories, and the tales of reporters who spent eight to ten years in jail for visiting China.

He says it was not always like this. For nearly 30 years after the 1932 establishment of the country's constitutional monarchy, Thai journalists remained quiescent, supporting whichever military regime controlled the government and considering few controversial issues. In the late '60s, however, Yoon and a few of his friends left the entrenched English-language newspaper, The Bangkok Post, and started a new type of paper, emphasizing more interpretative stories, more investigative reporting, and bolder editorials.

"In Thailand it is difficult to look at journalism as a detached career... Journalism in the Third World means you have a lot of involvement in what you write about. You are always advocating a cause."

"Perhaps we were so enthusiastic because censorship was so strong under the military government in the '60s," Yoon says. "We thought journalism was the main opportunity to make changes in the society, to provoke people to thinking about things they took for granted. We managed to start a new trend in journalism, putting out politically serious newspapers instead of the popular sensationalistic publications that abounded."

This new type of journalism has been coldly received by the Thai government. The country averages one coup every two years and with each new regime come new sanctions and restrictions on the media.

At one time officials were sent to all newspaper offices as soon as the papers came off the press. Those stories the government found subversive were painted over with black ink.

Since then the government has resorted to subtler methods. During the 1976 coup when police raided the capital's university, killing 50 to 60 students and arresting 3000 others, the regime imposed a total news blackout, closing all papers for three days. But, having no control over magazines like Time and Newsweek, which were published outside the country, they hired students and unemployed persons to tear the pages on Thailand out of thousands of periodicals before the publications were put on the newsstands.

TODAY CENSORSHIP is not as blatant. But the Revolutionary Party's decree No. 42, which empowers the government to close down papers with no legal recourse, and the all-embracing Anti-Communist law, remain ominous threats. "With no pre-publication censorship, editors play a dangerous game," Yoon says. "You take a gamble every time you go to press. You go as close to the truth as you dare, but you never know when you'll be shut down for something that appears in the morning paper."

Of course Thai journalists have developed a number of tricks for outsmarting the censors. Leaning forward slightly in his chair, a flicker of a smile on his face, Yoon spills a few trade secrets. "Papers are not allowed to print pictures of dead bodies which the government claims would create nauseating feelings," he says. "We get around that one by captioning the pictures 'mortally wounded' or 'taken minutes before death.' Thai police don't read English too well." When Thai troops were sent into Laos to fight with Americans, the government forbade any articles on the bilateral affair. The Nation Review reported that the government had denied sending troops into Laos. "That pleased the government, and of course everyone else knew what was going on," Yoon grins.

The paper and others like it have not always been this lucky. After the 1976 coup, the Nation Review was closed down for more than a month, and its executive editor was arrested. Yoon was accused of being part of an anti-government conspiracy. Still such threats to individuals have not deterred the men in Yoon's circles. "In Thailand it is difficult to look at journalism as a detached career," he says. "Journalism in the Third World means you have a lot of involvement in what you write about. You are always advocating a cause."

Probably the biggest problem facing journalism in Thailand today is the estrangement of the young. After the demonstrations and shootings of 1976, about 3000 students left for the jungle to join the Communist Party. "It was not so much that they were pro-Communist as that they were afraid of being liquidated. Because of the series of military takeovers which shut down newspapers, they were disillusioned with the constructive role of the press in changing society for the better," Yoon explains. A whole generation of new brains left the city, left the country, left the system."

"TO BE ABLE TO KEEP up an oppressive system you have to plug up the loopholes," Aggrey Klaaste, Nieman Fellow says. As news editor of one of South Africa's three Black papers, the Johannesburg Post, Klaaste's job is finding the holes the government hasn't closed. With the barrage of legislation restricting press freedom, it is a difficult and dangerous assignment. For Klaaste it has also become a mission.

In South Africa, quite simply, two kinds of news exist: pro-and anti-government. The five dailies and six weeklies published in Afrikaanin--the language of the white rule--are the voices of the Nationalist Party, the minority which gained control of the government in 1948 and instituted apartheid. The country also has 16 English-language dailies and 15 weeklies, two Black publications in English, and one in Zulu. With one exception, these papers are anti-government.