Penetrating the Iron Curtain. Chinks in the Iron Curtain allow Western influences -- from American Express to Donna Summer -- to seep into East Europe. In the past 40 years, East-bloc politics, economics, and culture have been affected by the West, sometimes subtly, sometimes openly.

AT first glance, the Iron Curtain looks like a turnpike toll stop. Inside the booth, the Polish border guard is listening on the radio to a Donna Summer disco tune. He takes the American passport, stares at the photo, and turns away. A half hour passes before he hands it back. At customs, a guard riffles through the luggage. He examines the Japanese camera equipment, as much out of fascination as duty. Then he waves his hand forward, smiles, and says dobrze -- good.

Instead of being solid and opaque, the Iron Curtain is full of chinks. The Donna Summer music and the fascination with the Japanese camera hint at how ``Western'' influences are penetrating into Eastern Europe.

When Winston Churchill coined his famous phrase in 1946, he feared that Soviet communism was spreading across Europe. Unless the United States stepped in and stopped the ``Russian peril to Christian civilization,'' the British statesman warned, all of Germany and the rest of Europe soon would find itself behind the Iron Curtain.

But even at that time of mounting cold-war tensions, the Iron Curtain was not truly iron. American journalist John Gunther traveled through Yugoslavia, Hungary, Czechoslovakia, and Poland in 1948 and found it more porous than he expected.

``Certainly,'' he wrote in his book ``Behind the Iron Curtain,'' ``the satellite states are isolated enough and it is Moscow policy to make them more isolated all the time, but some rays of light do get through, and it is my conviction that in time -- provided war does not come -- the satellites will want more and more contact with the West.''

His predictions have come true. Later in 1948, one Iron Curtain country -- Yugoslavia -- broke away from the Soviet orbit. The nation has since forged a reputation as being nonaligned and open.

The situation in Germany was also stabilized, and the Iron Curtain was moved several hundred miles westward from Churchill's limit at Szczecin. The richest and largest part of Germany was firmly entrenched in the Western camp. A safety net?

Many now see the Iron Curtain as a safety net. According to this view, no war has erupted in Europe because both East and West know that they cannot step over the dividing line.

``The Iron Curtain stops sparks from flying,'' says Theo Sommer, editor in chief of Die Zeit, a West German weekly.

Diplomacy has created a more permeable border. When Gunther traveled to Berlin in 1948, he was forced to fly, because the Soviets were blockading the city in an attempt to force the West out. Today, thanks to the d'etente of the 1970s, highways tie Berlin to West Germany, and transit visas -- albeit only for Westerners -- are given on the spot.

The southern flank has opened even wider because of Yugoslavia's defection. Gunther saw American troops defending Trieste against hostile Yugoslav communists in the surrounding hills. But in 1954, a compromise was reached. Yugoslavia kept the hinterland and Italy recovered the city.

The American troops pulled out, and neither Yugoslavs nor Italians now need visas to cross the border. Yugoslavs come to buy coffee, lemons, and jeans, goods that are either unavailable or cheaper than at home. Italians leave to sun on the Istrian beaches.

Yugoslavia, when under the Soviet thumb, depressed Gunther. ``By far the easiest way to describe Belgrade is to say that it is a Moscow in miniature,'' he wrote.

``Poverty and drabness; the disappearance of gentility; lack of all elegance and grace; a severely moral atmosphere; long queues everywhere; terrible shortages in consumer goods; emphasis on industrialization; widely inflated prices; intense xenophobia and suspicion of foreigners; inaccessibility of most officials and a heavy pall of bureaucratic secrecy -- these are characteristics common to both capitals.''

Today, Belgrade's new neighborhood shines with white skyscrapers. Its stores are packed with consumer goods. Prices are reasonable. And American journalists are welcomed with smiles.

``Can't you stay longer?'' asked information officer Branka Susa after making appointments for my two-day visit. ``Too few Westerners come to write about us.''

The Soviet bloc, too, is more welcoming than most Westerners might imagine. When Gunther visited Eastern Europe 38 years ago, he met almost no tourists. Officials in Szczecin say hundreds of thousands of Western tourists now pass through the border each year on their way to the Baltic beaches.

In the Soviet Union, most Western visitors come in groups and follow strict itineraries. Not in Eastern Europe. If a Westerner has a visa in good order, he can go where he wants, when he wants.

Life is much more ``Western'' than spy novels suggest. You can rent James Bond movies on video in Warsaw, use the American Express card in Prague, and buy the International Herald Tribune in Budapest.

A key reason for accepting these Western influences is the hard cash they bring from visitors. Eastern European countries use this Western currency to help pay for imports.

Just as important, Western culture is attractive to the East Europeans because they share a common heritage with the West. Mozart went from Salzburg to Prague and Chopin from Warsaw to Paris without feeling they were moving ``east'' or ``west.'' Today, Poles, Czechs, and Hungarians tell visitors that they live in Central Europe, not Eastern Europe.

Poles see the Soviets as historical enemies, and adore the West. Although they learn Russian at school, they refuse to speak it with visitors. They prefer English or French. They admire Western democracy and the West's prosperity. Even Communist Party members often boast of owning a stereo from Japan or a dress from Paris.

``The biggest compliment any Polish girl can receive,'' says Anna, ``is to be told she would look good in Paris.''

Elsewhere in Eastern Europe, similar Western influences are visible. In Prague, shoppers eye Nikon cameras. In Budapest, they munch Hungarian fast-food hamburgers. But both Czechs and Hungarians, who enjoy a more comfortable standard of living than the Poles, are less envious of Western prosperity. Although Warsaw's duck restaurant often is out of duck, diners in Budapest can sip turtle soup in the art deco splendor of the Hungaria caf'e.

Jozef in Prague is satisfied with his Soviet Zenit camera. ``It's fine for an amateur like me who only wants souvenir pictures of his family,'' he says. And Mariann in Budapest doesn't dream of Big Macs, even though a branch of McDonald's is planned for Budapest soon. ``The Hungarian hamburger is very good,'' she says.

History helps explain this more ambivalent attitude toward the West. Many Czechoslovaks continue to feel bitter about the English and French ``betrayal'' of their country to Adolf Hitler at Munich in 1938. Like the Hungarians, they say theirs is a small nation that must make an outward show of compliance with Soviet domination while using its innate intelligence and ingenuity to make the best of this unenviable position.

``The Poles are incurable romantics,'' says Michal in Prague. ``We are much more realistic.''

These distinct national traditions make it difficult to generalize about Western influences on the East bloc. Still, in varying degrees, the region does face common political, economic, and cultural pressures -- and these pressures look likely to open the Iron Curtain even more in the future. Soviet stranglehold loosening

During Poland's Solidarity days in the early 1980s, it looked as though more-open, pluralistic societies would develop in Eastern Europe.

To stabilize the region, Western pundits argued, the Soviets would decide they were better off conceding East European states more freedom at home in exchange for iron-clad guarantees that they would not leave the Soviet orbit.

Warsaw's declaration of martial law in December 1981 crushed the independent trade union Solidarity, and these hopes.

Still, East European observers say that over the years, the Soviet stranglehold has gradually loosened.

As evidence, they point to the length of each successive revolt against Moscow's orthodoxy. Although the Hungarian uprising in 1956 was crushed in just a few days, Czechoslovakia's ``Prague Spring'' in 1968 blossomed for seven months, and Poland's Solidarity era lasted for 16 months.

And in the last few years, Hungary and Poland have required most parliamentary seats to be contested by more than one candidate.

East European leaders now strive for at least a modicum of consensus. Although they tried to follow Soviet dictator Joseph Stalin in stamping out dissent, they have since come to accept what the Soviets would consider dangerous heresies. Economist Friedrich Hayek and novelist George Orwell are read at many universities. Private farms and shops flourish. More and more people flock to church.

``You have to know where to look,'' writes Timothy Garton Ash, a British expert on East Europe. ``If you look from above, at the formal, official structures of the system and the empire, you may well see `no change' or, at best, very small change.

``But if you look from below, from the point of view of the individual man or woman living in one of these countries, then a great deal has changed, is changing, and will continue to change.

``What you find in all these countries, though in very different shapes and degrees, are European societies which are increasingly active, coherent, and unillusioned, well-informed and sceptical, yearning towards the capitalist democracies of the West.'' Adjusting to the marketplace

East European leaders say that they must move away from their centrally planned economic system.

The centralized system served a useful function after World War II, creating industrial societies in what used to be a predominantly rural part of Europe. But East-bloc products are becoming less and less competitive on the world market.

To correct that situation, officials admit they need to introduce more market forces, private initiative -- and Western credits. Even in Czechoslovakia, where the word ``reform'' was banned until Soviet leader Mikhail Gorbachev came to power, officials now whisper that such economic reforms are inevitable.

It remains uncertain how far the East Europeans will go. Even in Hungary, the East-bloc country best known for economic experimentation, the government insists on large amounts of central control. Hungarian officials fear that too strong a dose of market medicine will produce unwanted side effects: inflation, unemployment, and most of all, a loss of political control.

``The major question facing the region is whether it can make the structural adjustment'' that would modernize its economies, says Ed A. Hewitt, an East European specialist at the Brookings Institute in Washington, D.C. ``So far they haven't made much of an effort, but now at least they're talking a good game.'' East Europeans loosen their ties

In the 1950s, East European communists inveighed against ``capitalist'' dangers such as Coca-Cola and rock music. They also attacked ``bourgeois'' culture from the past, such as the music of Bela Bartok, one of Hungary's most famous composers.

No longer. To varying degrees, East European leaders use national symbols to buttress their claim to power. The East Germans recently celebrated Martin Luther's birth, and the Hungarian National Orchestra often features Bartok.

Similarly, Western culture is too popular to block out. After criticizing rock music for spreading ``nihilism and a cynical approach to life,'' Czechoslovakia this summer sponsored a rock festival that for the first time featured ``underground'' bands. And in July, the Hungarians permitted the English rock group Queen to play before a packed stadium audience.

``We used to be scared that these things threatened socialist values,'' says Ivan Berendt, president of the Academy of Sciences. ``Now we have matured.''

First in a series of occasional articles.