Thirty years ago today, most of Seoul was sleeping late on a quiet Sunday morning as rattling Russian-made tanks, looking like war helmets on treads and full of invading North Korean soldiers, began to fill the highways toward town.

"A few months before, an American general had concluded we had so many rice paddies, tanks couldn't operate here," said one Korean newsman recently. He had to hide for three months when the enemy reached the city.

Since then, residents of Seoul do not like to be thought of as unprepared. Today, on the 30th anniversary of the invasion from the north, they had an air-raid drill.

Sirens blared at 3 p.m. Drivers jumped out of taxis and into shops. A pink smoke-marker went off in the driveway of the Chosun Hotel. Young wardens yelled at sightseers to stay inside.

The drill is a monthly occurrence, made a bit more special by the anniversary and the prospect of a rare night drill tonight, but all it required was to step inside for 15 minutes.

Down in the hotel's underground mall, along the section dubbed the Champs-Elysees, Seoul people passed the time checking out shop after shop of jewelry, cameras, watches and well-tailored clothes.

They had no such goodies to lose in June 1950, but teenagers carrying loads of explosives hurled themselves at the North Korean tanks. South Koreans wonder now whether their pampered young, never having suffered invasions such as those that twice occupied Seoul, would today resist so ferociously.

Government spokesman who cite the threat from the north as a reason for tight controls on dissent are regularly lampooned on college campuses. Official anniversary remembrances today were filled with appeals to young people: "You may not feel the tragedy of the war," said the message to young soldiers from Defense Minister Choo Young Bock, "but you must be aware that your parents or relatives experienced that tragic event."

From atop the Songag observation post, the border between north and south, which soaked up so much blood three decades ago, spreads itself lush and green before the eye. Small woods over much of the hilly country. Green rice fields are farmed by lucky South Korean who escape taxes and conscription because of the peculiar political status of the Demilitarized Zone.

If one squints and looks in the right direction, a tall column can be seen on the North Korean side, glistening in the sun. It is a 45-foot-high statue of Kim II Sung, Pyongyang's "maximum leader."

The South Korean soldiers who man the observation post say there are North Korean tunnels being dug somewhere out there. There display at the observation post photos of two U.S. soldiers being murdered with axes by North Koreans during a 1976 Dmz altercation.

It seems little more real on a beautiful summer day than the small village on the North Korean side, vacant of people, where the lights go on automatically each evening at sunset.

Lt. Gen. Kim Yun Ho commander of the 1st Army Corps defending the northwest approaches to Seoul, is an energetic, well-read man. He likes to both quote Chou En-lai, China's late premier, and recall that half his classmates at the Korean Military Academy died in the bloody battles of 1950 and the 1951 against North Korean and Chinese troops.

He watches with approval at the Army special forces training camp as young Koreans yelling "Ranger! Ranger!" slide down off a mountaintop on a steel wire and splash into a pool of chilly water.

The South Korean Army still seems as tough as it was when it terrified the Vietnamese 10 years ago, in the small area assigned it north of Saigon. Kim, who served in Vietnam and spent some time in Washington, says his soldiers are tougher, and better educated, than many of the Americans stationed here, but both Koreans and Americans, he says, are ready to fight.

"Our young people can appreciate the threat," he said. His own son, however, is at the moment a student at one of the Seoul universities that have been in political turmoil.

"We have different opinions on some things," he said, "but we discuss them frankly."

What is your son studying?

"Political science."

Would you like him to make a career in the Army?

"He doesn't want to."