WORLD CUP 2002/Korea Letter: This morning in Seoul you'll be able to inspect the centrepieces of the great squares and examine the fringes of the broad thoroughfares and you won't find a flower trampled, a gutter littered, a window broken.

You'll find no evidence of the millions who poured onto the streets in their red T-shirts which bore the legend Be The Reds. They'll have vanished, tidying up as they went home because for them being part of the greatest day in Korea's history means doing just that.

We rowdy paddies are a different story of course. The last of us and the most hung-over of us were haunting the airports of Seoul and Tokyo yesterday while our countryfolk who can't be trusted to line the streets and wave at a passing bus, were being herded up to the Phoenix Park for a celebration with the tame taste of official Ireland about it. Not being in a position to judge whether the thousands tidied up as they went home from the Fifteen Acres, we won't make odious comparisons. But we could learn something.

The Korean National Police Agency said 4.27 million fans took to the streets nationwide, including 1.76 million in Seoul alone. Officials said it was the highest number of people recorded in public gatherings in South Korea's history. It beat the previous record for outside gatherings, including the roughly one million pro-democracy protesters who gathered in Seoul in 1987.

Yesterday was an extraordinary day in this part of the world. Japan and Korea, knotted together for the purposes of this World Cup, are as different from each other as England and France are. As different and as fiercely rivalrous. They are only co-hosting because neither country could stand to lose to the other in the bidding process. They have outdone each other like nouveau riche neighbours in the preparations for the World Cup. When Japan hit the economic reef in 1999, there were public statements to the effect that building 10 venues in each country was excessive. Well, you do what you like, said the South Koreans, we'll be building 10. Then the Japanese shut up and did likewise.

And then there's the small, unforgiven matter of Japan having occupied Korea for 35 years. The surface of Japanese life is a comedy of manners, an endless cavalcade of formalities and customs which charm the newcomer and conceal what people who have lived here a long time discover to be a deep-rooted disdain for foreigners. Last week in Sapporo, departing English fans enjoyed the unique sight of a uniformed young woman running through the airport terminal late for work. Embarrassed by her lack of decorum she bowed at everybody she passed as she ran. She looked like a water hen on speed.

The Koreans are a different kettle of fish. Cooked fish, for a start. They enjoy a more informal, philosophical existence than their neighbours. In Japan, one risks losing the elevator altogether as all parties gathered at its doors bow and beckon to each other to step aboard first. In Korea you'd be trampled to death and the last thing you'd hear was hearty laughter. They enjoy a belly laugh, the Koreans.

And their bellies are rippling with laughter this morning. From the time the World Cup was granted to these countries the unannounced competition within a competition was to see who could stay in the longest, Japan or South Korea. Both nations appointed foreign coaches, but the Japanese got a jump on the Koreans and got their man first.

Phillipe Troussier, who looks more than a little like the actor Rick Moranis, arrived in 1998 and launched his reign with a friendly against Egypt. The following year the Japanese side finished second at the world under-20 championships, becoming the first Asian side to reach the final of a FIFA- sanctioned event. The Japanese were too stifled by politeness to sing it, but in private moments they hummed their tune. Are You Watching, South Korea?

The following summer, Troussier took an under-23 squad to the Sydney Olympics and steered them to the quarter-finals, Japan's best performance in the competition for 32 years. A month later, the full Japanese squad won the Asian Cup. The following summer the only goal they conceded in the Confederations Cup was to France in the final. The French had already toasted the South Koreans 5-0 in the first round.

In contrast, Guus Hiddink had only 18 months to create a squad for the World Cup. By the time he took over, the South Koreans had enjoyed a gutful of their perfect neighbours. Typical of Korean luck would it be for them to be overshadowed by their old enemies. The Koreans had, after all, nurtured the first professional league in Asia, the still extant K League (founded 1983), only to see it eclipsed by the vulgarity and imported stars of the unimaginatively named J League. They plugged away anyway.

They completed an airport the size of a city in Incheon and built a Bertiesque stadium nearby, even though the city has no team. The city has its history, though. English sailors from a ship called the Flying Fish landed here in 1880 and introduced soccer to the local populace. They've had to wait a long, long time, and then, a month before the World Cup, they put their heads in their hands as Hiddink announced that the World Cup had probably come a year too early for his team.

The signs weren't promising. Although some of the squad are playing in their fourth World Cup, the record in five previous appearances in the World Cup was played 14, lost 10, drew four. That includes a 9-0 hammering from Hungary and a 7-0 wipe-out against Turkey.

The greatest Korean memory of World Cup play belonged to the dour neighbours to the North. In 1966, at Goodison Park, North Korea led a legendary Portuguese team by three goals to nil after 25 minutes of a World Cup semi-final. Then Eusebio clicked into gear and scored four goals and the heroic North Koreans wound up losing 5-3.

They'd already beaten Italy up at Ayresome Park, Middlesbrough, however. Famously, the Italians had gone to see the Koreans play before the tournament and pronounced the experience to be like watching una comedia di Ridolini, Signor Ridolini being a Chaplinesque Italian film star of the 1920s. Italy lost 1-0 and went home in shame with their manager sacked instantly. The goalscorer, Park Doo-Ik, went on to become a dentist.

Yesterday his South Korean brethren bothered the Italians all afternoon like a nagging cavity, and when Ahn Jung Hong, their Italian-based striker, nodded the golden goal in extra-time it was no more than they deserved and no less than the greatest upset in recent World Cup history. It didn't need any sweetening, but the fact that Japan had gone out against Turkey hours earlier, well . . .

Hiddink had built his team in a style the Italians would understand: from the defence upwards. In a rematch against France a couple of months ago Korea closed the margin to a single goal and played with different central defenders in either half. They set up training camp in Europe in March and went five games (Tunisia, Finland, Turkey, Costa Rica and China) without conceding a goal.

Things have improved between Korea and Japan. Hundreds of school teams from each country have been visiting their neighbours and there is a feeling that both nations are being judged together and are in this together.

Across the sea in Japan yesterday, though, they could hear the laughter of the nation which laughed last. They'll be hearing it at least until the quarter-finals are over.

And we Irish? Forgotten, but not gone entirely.