SEOUL, 25 June — South Korea declared July 1 a national holiday to celebrate the country’s World Cup success as it braced for the biggest street party it has ever seen for today’s semifinal against Germany.

With millions of fans expected to pack major boulevards to urge the national team to pull off a new shock win, the government added to the nationalist fervor by declaring the day after the World Cup final a national holiday.

Banners encouraging South Korea were strung from skyscrapers across the capital. Sales of red T-shirts have been so high that manufacturers are running out of cotton cloth.

“Let’s go to Yokohama!” declared a huge banner hung over a giant television screen on the side of a major hotel in the Gwanghwamun district in central Seoul.

The capital is expected to see a new red tide wash through for today’s match at the Seoul World Cup stadium.

Police forecast conservatively that more than seven million fans, 15 percent of the 48 million population, would take to the streets to roar on South Korea against Germany for a place in Sunday’s final in Yokohama, Japan.

After the deaths of three people in accidents during Saturday’s quarterfinal against Spain, more than 33,000 police are to be deployed, including 7,000 in Seoul alone.

Seoul city government which expects more than 2.5 million fans in the streets of the capital, is mobilizing some 5,000 emergency fire fighters to help fans.

South Korea, which had never won a single game in the previous World Cup finals, has now shocked the world with a series of wins over top teams including Portugal, Italy and Spain.

Media have called the run of wins a “World Cup miracle” or “World Cup myth” as few Koreans had initially expected such success. Now the sentiment has turned into almost hysteric confidence.

“Our run has not yet stopped,” read another banner on a high-rise insurance company in central Seoul.

Skyscrapers have had to change their banners as the team has progressed. Messages have changed from “Let’s go to the round of 16” to “Let’s go to Yokohama!”. The state post office declared “World Cup Victory Is In Sight” and put up huge soccer balloons from its main building.

With the South Korean national flag and red t-shirts becoming the most symbol of support, manufacturers are running out of material, media reports said.

“Workers have had little time to sleep in the past weeks because of the huge demand,” one flag factory manager told YTN television news.

Some reports have said almost 10 million “Be The Reds” t-shirts have been sold since the start of the tournament on May 31.

The slogan was thought up by the Red Devils, South Korea’s fanatical supporters club, which has promised that Germany will get the shock of their lives when they walk on the pitch for today’s semifinal.

Kim Yong-Il, head of the Seoul chapter of the Red Devils, said members were working on a giant slogan that will “really shock the world”.

Without giving away the message, Kim said it would be even more provocative than the “Again 1966” card display that thousands of fans put up in the second round match against Italy last week.

Italy’s coach Giovanni Trappatoni complained the reference to Italy’s 1-0 defeat by North Korea at the 1966 World Cup finals was intimidatory. But FIFA insisted it could do nothing as long as there was no racism or threat of physical violence.

Red Devil leaders said the message for Germany will be kept secret until just before the match.

“Our members are very tired as they have worked so many days and nights,” said Kim Yong-il. “However, we get refreshment when thinking of Korean players giving it their all. Our message this time will really shock the world,” he vowed.