From his hilltop position among the craggy, forested peaks of Marble Mountain a few miles south of this city, Le Van Chinh watches the stretch of coastline once called China Beach for any signs of assault by sea or air.

A member of the Hoa Hai village militia, Chinh, 19, is not sure who might want to attack the central Vietnamese coast these days. But he has a Soviet-made antiaircraft machine gun within reach a few paces from his thatched lean-to for just such an emergency.

Like more than half of Vietnam's population of 60 million, Chinh was not born yet when a battalion of U.S. Marines splashed ashore near Da Nang on March 8, 1965. Those marines, among the first of about 3 million U.S. troops to serve in America's longest war, initially were greeted with garlands of flowers and banners of welcome. They soon became bogged down in a frustrating and ultimately futile conflict with an implacable enemy.

The enemy included Chinh's father, who fought for a Communist Vietcong guerrilla unit that once hid out in the secret caves and tunnels of Marble Mountain overlooking a large American base, the headquarters of the 1st Marine Regiment.

Despite that heritage, and although his native Hoa Hai was cited as a "hero village" for its inhabitants' contributions to the Communist war effort, Chinh seems only dimly aware of that initial American landing. And he said he does not know much more about the war that ended 10 years ago when the North Vietnamese Army routed the U.S.-backed forces of South Vietnam and captured its capital, Saigon.

Today, the Hanoi government is doing its utmost to remind people of that victory with a series of celebrations marking the capture of South Vietnamese cities in the spring of 1975 during the "Ho Chi Minh offensive," named for the late North Vietnamese president. After parades and other festivities in Ban Me Thuot on March 10, Hue on March 26 and Da Nang on March 29, the celebrations will culminate April 30 with a major show to fete the "liberation" of Saigon, since renamed Ho Chi Minh City.

Vietnam today certainly seems to need something to celebrate. Ten years after the victory in the south, which led to the 1976 "reunification of the country" under Communist rule, Vietnam in many ways is still recovering from the war.

The war resulted in the death or wounding of 4 million soldiers and civilians in the two Vietnams. One of the world's 20 poorest nations, but maintaining the world's fourth-largest army, it has failed to provide more than bare subsistence for most of its people, let alone realize its dreams of breaking into the ranks of Asia's powerhouse economies.

Its apparent determination to dominate neighboring Cambodia and Laos has left it with few friends internationally outside the Soviet Union and has contributed to a state of hostility with China.

Nearly a million refugees have fled the country. And tens of thousands of citizens associated with the southern regime have been interned in camps around Vietnam for long periods of "reeducation."

Increasingly isolated, Vietnam's main achievement seems to have been to tread water for 10 years, constantly haranguing its people to work harder and to remain vigilant against external threats.

For these 10 years, China, the United States, Japan and other countries "have been cooperating to throttle us," said Hoang Tung, a senior member of the Communist Party Central Committee in Hanoi. "Well, we are not dying. We're tired, of course. But we still exist."

For the Vietnamese leadership, the 10th anniversary of the "liberation" of Saigon is clearly an occasion to rally the people for further sacrifices toward achieving a "socialist transformation" of the southern half of the country. Yet, somewhat ironically, it is also shaping up in Hanoi's eyes as an opportunity to promote improved relations with the United States at a time when American attention will be focused on Vietnam again.

In what amounted to an appeal for diplomatic relations with the United States, Vietnamese Foreign Minister Nguyen Co Thach said recently that the 10th anniversary "could remind both countries that the time is ripe for normalization." In an interview in Hanoi, he added, "Ten years have passed. It is enough to heal the wounds of war."

"We consider that the war is over now, and the U.S. administration that was involved in the war is also in the past," said Vice Premier Tran Phuong. "We want to develop relations with the United States in the same way that we have with other countries. That means we could start trading, and we would welcome investments from Americans."

From the U.S. point of view, the main obstacle to that aim -- one that Vietnamese officials prefer to ignore in their overtures for improved relations with the West and an end to their current economic isolation -- is the presence of 160,000 to 180,000 occupation troops in neighboring Cambodia.

The last decade has seen China replace the United States as Vietnam's number one national enemy. Washington's opposition to the Vietnamese invasion of Cambodia in December 1978 and its support for noncommunist Cambodian resistance guerrillas are thought to preclude the opening of diplomatic relations with Hanoi anytime soon. Cataclysmic Vietnamese Losses

And, certainly, the wounds of war still run deep.

From the time the first marines arrived until the last U.S. combat troops withdrew in 1973, two years before the ultimate Communist victory, the Vietnam war cost the lives of nearly 58,000 Americans and maimed thousands more. Among those presumed dead are 2,477 still missing in action, a number of them known to have been captured alive.

Besides the heavy toll in lives, the war is estimated to have cost U.S. taxpayers more than $120 billion. It spawned one of the most divisive periods in U.S. history and changed international perceptions of the United States. The name Vietnam became synonymous for Americans with military debacle, futility and waste.

For the Vietnamese, the war was nothing short of cataclysmic.

It is estimated that the total Vietnamese casualties on both sides made up about 10 percent of the population. That would be roughly proportionate to U.S. losses of 20 million.

The Communist side -- both North Vietnamese troops and the Vietcong guerrillas in the south -- took losses estimated to total 600,000 to more than 1 million combatants killed. In addition, more than 250,000 South Vietnamese government troops died in the war.

According to officials in Hanoi, the number of Vietnamese still missing in action is in the range of 100,000.

The United States made Vietnam the most heavily bombed country in the history of warfare, dropping more ordnance on it than on all theaters combined during World War II.

In addition, according to Vietnamese officials, about 40 percent of South Vietnam was sprayed with chemical defoliants. Congressional Quarterly figures indicate about 12 percent of the south's acreage was "destroyed."

Yet, for all the damage it caused, the United States also showed considerable restraint. Contrary to Hanoi's wartime propaganda and U.S. critics of the war, the North Vietnamese capital was never subjected to indiscriminate "carpet bombing" by B52s. Today the picturesque city of lakes and tree-lined streets remains intact, its turn-of-the-century French colonial buildings slowly crumbling from disrepair rather than from the effects of aerial bombardment.

Elsewhere, however, the physical impact of the war is still much in evidence.

Parts of the area north of the former demilitarized zone at the 17th Parallel -- the most heavily bombed part of the country during the war -- still look like a moonscape. To weather the bombing, the North Vietnamese dug tunnels and underground chambers as much as 83 feet deep -- many now preserved as historical monuments.

Quang Tri, a town just south of the DMZ, was obliterated by U.S. bombing when Communist forces overran it in 1972. Today, cows graze in a field littered with scrap metal in what was once the renowned old citadel.

Mines and unexploded ordnance have killed thousands since 1975 and continue to cause casualties.

"Until now we have not been able to clear all the mines and bombs," said Nguyen Tien Binh, 39, a former North Vietnamese Army sergeant who took part in the 1972 battle for Quang Tri and settled there later.

At Khe Sanh, near the border with Laos, the scene of a fierce battle between Communist and U.S. troops in 1968, authorities say about 400 persons have been killed by mines since 1976. According to Kien, a 22-year-old villager, the latest victims were two brothers who set off an explosion in March while tilling the soil about three miles from Khe Sanh, now the center of a New Economic Zone of collective agriculture.

Ngo Duy Dam, a member of the People's Committee that administers Hue, said that about 700,000 bombs and mines remained in the soil after the war in the province of Binh Tri Thien, an amalgamation of three former provinces that now overlaps the former DMZ.

At numerous sites along Highway 1 in this narrow central part of the country, Vietnamese are busy digging up shell casings and collecting junked American tanks and other abandoned war materiel to be exported as scrap or melted down in steel mills.

"Martyrs' cemeteries" near villages along the highway dot the countryside with acres of tombstones, many of which are symbolic because the bodies of the war dead never have been found.

An unusually high percentage of mothers give birth to deformed babies, a phenomenon that Vietnamese doctors blame on the use of American defoliants. At Tu Du hospital in Ho Chi Minh City is a room that normally is kept locked. It is a veritable chamber of horrors. On shelves inside are jars with preserved fetuses and stillborn babies with hideous birth defects, including several Siamese twins and some with bloated heads filled with liquid.

According to Dr. Nguyen Thi Ngoc Phuong, a 1982 study showed that 64 percent of mothers who gave birth to deformed babies at the hospital had been exposed to the defoliant Agent Orange. She said South Vietnam had the world's highest rate of hydatidiform mole, a rare and potentially cancer-causing reproductive defect in which pregnancy occurs without development of a fetus.

In the Mekong River Delta village of Thuan Dien in Ben Tre Province, Mai Thi Nghiem said she was four months pregnant in 1968 when U.S. aircraft sprayed Agent Orange over the area, a Vietcong stronghold. Her son, Vo Van Trac, now 17, is a hopeless cripple with deformed legs and feet who resembles victims of the mercury poisoning in Japan's Minamata region in the late 1950s. His face contorting in grimaces and fists clenching spasmodically, he cannot speak but wails almost continually.

Whether or not such deformities were caused by Agent Orange as the Vietnamese assert, war cripples abound, some of them maimed when they were children. One, a boy named Thu whose right leg and right arm are missing, said he was injured by an artillery shell when he was 6 years old. He does not know which side fired it.

Now 18, Thu sells lottery tickets for a living in My Tho Province in the Mekong Delta and moves about by hopping barefoot on his one leg.

In My Tho and other provincial towns, the faces of Amerasian children frequently appear among crowds of street urchins. Many, like Tran Minh Tan, 15, and Nguyen Danh Duong, 14, eke out a living by doing menial work such as collecting garbage. Neither knows who his father was.

According to Vietnamese officials, the Americans "left behind" about 15,000 Amerasians in Vietnam and have been dragging their feet on resettling them in the United States. U.S. officials in Bangkok said more than 2,400 Amerasian children and nearly 3,000 relatives have been brought to the United States under the U.N.-sponsored Orderly Departure Program, which has allowed nearly 85,000 refugees to leave the country legally during the past five years.

Now U.S. officials estimate that 10,000 to 12,000 Amerasians remain in Vietnam, some of whom do not want to leave. Currently on the U.S. waiting list for resettlement are 6,918 Amerasians and 13,211 relatives.

Invisible legacies of the war also persist in the minds of many Vietnamese, as they do in the memories of U.S. combatants. While Americans here seem to encounter little or no hostility from Vietnamese these days, rancor occasionally surfaces in talks with peasants such as Le Thi Mang, a 65-year-old woman with betel-stained teeth. She wears traditional black pants and shirt and a conical hat.

Asked what she thought of Americans as she visited the Hue citadel recently, she replied, "they are cruel, extremely cruel." She recalled an incident in 1965 in which American and South Vietnamese troops entered her village about 18 miles north of Hue and threw grenades into a Vietcong tunnel.

"Four cadres of the revolutionary forces were killed," she said, including her brother.

"The Americans committed so many crimes," said Huynh Thi Ba, 42, a former Vietcong cook who now sells soft drinks to tourists at Marble Mountain. "So many people in our village had to be separated, and so many relatives were killed." She said her first husband, a Vietcong guerrilla, "sacrificed his life" when his unit was hit by an American rocket in August 1968.

She added, however, "I am very happy that we are at peace now. We try to concentrate on building our houses and farming our land. We are not so rich, but we have enough to live on."

Although it may seem an obvious point, the absence of war represents perhaps the most important change since 1975 for many Vietnamese, especially the peasants who make up about 80 percent of the population. Vietnamese troops still may be fighting and dying in Cambodia, and to a lesser extent in Laos, but the homeland is quiet, and rural life can go on much as it always has.

"The most important thing is that we don't have to be in the Army," said Huynh Nhan Trung, 42, a former South Vietnamese private who lives with his seven children in Chu Lai village near the former base of the U.S. Army's Americal Division. "We can be with our families and work the land. That's the biggest change."

He said his standard of living had declined since the war, but he would express no opinion on the Hanoi government. "As far as ordinary people are concerned," Trung said, "we think we can live with any government."

To be sure, Chinh, the young militiaman posted on Marble Mountain, surveys a peaceful scene.

Groups of schoolchildren, many of them wearing red kerchiefs of the Communist Pioneer youth organization and badges signifying good behavior, take field trips to the mountain's Buddhist pagodas and shrine-filled caverns. Guides proudly explain the clever use of the mountain by Vietcong guerrillas who disguised themselves as monks and secretly established a field hospital and other facilities there in the knowledge that the Americans -- respectful of the Buddhist holy places -- had put them off-limits to GIs. Cam Ranh "a Soviet Base"

Like most Vietnamese these days, the schoolchildren seem to assume that every foreigner is Soviet, frequently calling out "Lien Xo," or "Russian," to visitors.

With up to 48 percent of the population under the age of 15, according to official estimates, many Vietnamese are too young to remember the American presence. And the reference points have changed.

Indeed, Soviet, Polish and other Eastern European tourists are the main clients of a new hotel within sight of Marble Mountain on nearby China Beach. There they sunbathe as Soviet-supplied MiG jets take off from the Da Nang air base and Vietnamese fishermen engage in their traditional fishing method of using grenades.

According to western diplomats, the Soviets have several thousand advisers, technicians and other personnel in Vietnam, most of them stationed at the former U.S. base of Cam Ranh Bay, where Moscow maintains a large Navy and Air Force presence.

A senior Pentagon official said recently in Bangkok that 14 Soviet MiG 23 interceptors are now based at Cam Ranh Bay and that port facilities there service an average of 25 Soviet naval ships a day.

"It's a Soviet base," the official said. "There's not a whole lot of Vietnamese in there." He added, "I think it shows a pattern of increasing Soviet presence in Vietnam, and that's a matter of concern. It's a price that Vietnam has to pay for the Soviet support necessary to conduct its operations in Cambodia."

For their part, Vietnamese officials concede a certain dependence on the Soviet Union but deny that this makes them Soviet tools.

"Now our economy depends much on supplies from the Soviet Union," said Deputy Premier Tran Phuong. However, he added, "in our relations with the Soviet Union, they don't force us to do anything. Vietnam is not letting anyone force us to do anything."

Mixed in with this defiantly nationalistic outlook and stubborn pursuit of independence, traits that carried Hanoi through 30 years of warfare, seems to be a conviction that the future will be brighter, that the worst is over.

Cu Dinh Ba, the acting chief of the Foreign Ministry's North American department, summed it up this way:

"On the occasion of the 10th anniversary of the liberation of Vietnam, we have a chance to look back at the past, and also to look forward to the future. Our people are very confident for the future, because the period of the most difficulties has passed. It is time for us to move forward."