In this lush green haven just south of Gettysburg, you can smell the corn for miles, but the 10 men mulling before game boards at Western Maryland College have been closeted inside for a week.

Moving clam-shaped tokens across two-foot-square wooden boards, they have found their sylvan retreat inside the mind, courtesy of the ancient game of Go.

Once an obscure obsession in this country only of Oriental game buffs, Go has reached some sort of occidental plateau here, where the First American Go Congress winds up tomorrow, cosponsored by the American Go Association and the Greater Washington Go Club.

Sixty-five participants are attending the congress, coming from as near as Washington and as far as West Germany for the lectures, workshops, tournaments and nuggets of wisdom from four visiting professional players from Korea and Japan (two of the Go mother countries). Two more experts and about 60 more Americans are due today and tomorrow for the Eastern United States Go Championship.

There is nothing obvious about Go. The game pits two contestants against each other and, in a superficial western nutshell, the trick is to gain as much territory as you can and surround your opponent's pieces. But you can't be martial about it. The execution is as complex as the premise is simple, involving a visionary ability to see the dynamics of the game quickly.

"You have to develop a new way of thinking," says typographer and Go participant Bill Buckley. "It involves lots of intuitive moves. You must see the entire board and all the interrelationships. That's the difficult part."

It's 7:30 on a Thursday night and the Westminster Ten are playing a simultaneous game. That is, a visiting Korean Go professional is playing all of them at once. A study in quiet intelligence, the bespectacled Sam-Jho Chun walks around the tables, pausing before each board only briefly to make his move. His American opponents, somewhat baffled by the microconfusion of it all, agonize over their next plays. When Chun reaches lightly in the black plastic bins and, cradling a white token between index and middle fingers slaps it lightly on the wooden boards, they nod or shake their heads as if to say, "Cripes, I shoulda seen that."

"Go is construction, not destruction like chess," says German participant Jochen Fassbinder, who paid his own way from Bremen to join the congress. "You need several lives to master it." He reiterates a favorite Go player's statistic (which tends to vary in figures): "There are more possibilities play combinations in one game of Go than all atoms in the universe. The atoms total 10 to the 80th power. The possibilities in Go are 10 to the 700th power."

Chess, by comparison, provides a paltry 10 to the 70th power, according to Paul Schofield, of Santa Cruz, Calif., another participant. But then chess is played on the squares of the board and Go on the intersections.

Fassbinder is a shodan, which is the lowest rung of professional-level status. The professional ratings, known as dan, range from 1-dan to 9-dan (a 9-dan is considered a Go genius). Beginners (insei) are given kyu ratings, which are inverse. Thus, a 1-kyu is the level before shodan but, if you are a 30-kyu, you probably have trouble crossing the street.

The other participants rate from low kyus to 6-dan. Most are men, both young and old, and the majority are past and present chess players with interests or backgrounds in the physical sciences. They are universally and humbly bound by a disciple's awe of the game -- which ironically has little, if any, relationship to chess or western linear thinking.

"Go intrigued me more than chess," says Schofield, a 34-year-old poet, former chess tournament player and 4-dan veteran. "The strategy is more complex and varied. Go has a far greater size of board than chess, with 19-by-19 lines . The combinations increase to exponents beyond our imagination."

Hugh Albright, one of the Thursday simul-players, is a mathematics professor at La Salle College who has played Go for five years. "I came across a book on Go 40 years ago," he says. "But I never had anyone to play with." Now he plays once a week at a small Go club in Philadelphia.

In Manhattan, says participant Stow Kelner, a member of the Manhattan Go Club, many people are "into it . . . There's a lot of computer industry there. I think Go draws that kind of . . . anal mind."

Back at the Thursday night game, the classroom is silent, except for the cool rumble of the air conditioner at the far end. As the time advances into two, then three, hours, the energy flags and the sighs and exclamations begin.

"Oh my God," says Seth Goldstein, a 26-year-old New Yorker, after the 6-dan Korean master has made a move. He pores over the board.

"I think I'm ahead," he says decisively. He looks over the board again. "I'm losing," he says.

The results are not as decisive as expected. Chun defeats only seven of them.

"Miraculous!" says Kelner of his win. "It was an oversight on Chun's part . I won with an atari a sort of checkmate ," he says, pointing to a combination on one edge of the board. "This is like some little leaguer beating Pete Rose."

"I won by 16 points," says Rochester, N.Y., resident Neal Gafter, a 1 1/2-year Go neophyte. After the game, Chun gives him an unofficial 4-kyu rating. The third winner, Joel Sanet, is a physician from Miami who has practiced in Japan. Ranked 1-dan in the United States, he received an unofficial 4-dan rating during his Japan visit.

As the participants know, Go is no Trivial Pursuit. "It's a pretty severe discipline," says Haskell Small, who heads the Greater Washington Go Club and is overseeing this week's events. Go pros, primarily from China, Japan, Korea and Taiwan, have played the game for most of their lives, where the 4,000-year-old game is a national tradition.

They start young in the Orient. Noriyuki Nakayama, a Japanese visiting Go professional animated behind his thick-lens glasses, says children are encouraged to get familiar with the game from the age of 3. The insei (would-be Go professionals) start from 7 years old. The best learning occurs between 13 and 15, says Nakayama, who started at 29, and the successful students become shodan. From then on, their aim is to play as many matches as they can and to improve their dan ratings.

"In high society, it is seldom that they cannot play Go," says visiting expert Jong Hyun Hong, a 6-dan and the official master of the Korean Go Association. He estimates there are about 5 million amateurs and professionals in Korea.

The ultimate Go player, he says through a translator, "hates to lose and must have endurance . . . First is talent, second is age and third is attitude -- the person's behavior and whole personality.

"When they see a board," says Hong, that player "will know who will win and who will lose. They have computer in the head."

Go professionals are more than just revered by disciples. Some players make up to $500,000 a year from sponsored tournament matches, according to Small. One of the top Korean players, says Hong, makes $100,000 a year.

The game has long been worldwide. The European Go Congress had its 29th congress earlier this year in Holland, and the American Go Association, though numbering fewer than 1,000 members, celebrates its 50th anniversary this year.

"When you learn, you want to know all the answers," says Marilyn Stern, a New York writer who wears a necklace bearing "Go" in Japanese characters. "But you almost never get an answer. Every time I'd ask a question [at my Go club] the players would burst out laughing. I was so rigid in my thinking, and Go is such a fluid game."

For her, the essense of Go is simple: "Ultimately you're playing yourself.