Japan intervened Monday in the foreign currency market, lowering the value of a strong yen that has handcuffed major Japanese exporters and hindered the country’s economic recovery.

The unilateral move came shortly after the yen soared to a post-World War II record of 75.31 against the dollar. After the Japanese government’s mass sell-off of yen, the currency fell more than 4 percent, to 79.2 against the dollar.

Finance Minister Jun Azumi said Japan will take further action, if necessary, to stave off “downside risks” to the world’s third-largest economy.

As Japan has struggled to recover from the economic devastation of the March 11 earthquake and tsunami, the persistently strong yen has turned into a barrier for Japanese companies, making their products more expensive overseas and trimming the foreign earnings that they repatriate.

Months of lower-than-expected profits have left these companies pleading for help — and looking increasingly to China and Southeast Asia as bases for new, less expensive factories.

Japanese officials speak often of a scenario where business here hollows out, with even the country’s iconic companies eventually operating largely overseas. The impact of such an exodus, which is already starting, would trickle down to the small- and medium-size Japanese companies that depend on major companies to order their products.

Japan’s earlier efforts to weaken its currency — this was Tokyo’s fourth intervention in the past 14 months — have offered only short-lived relief, with the yen returning to its pre-intervention level within days.

Economists say that Japan will continue to struggle with currency appreciation so long as investors view the yen as a haven — a smart bet amid concerns about U.S. stagnation and a sovereign debt crisis in Europe.

The strong yen, though, “doesn’t reflect our country’s real economy,” Azumi said. He declined to say how many yen were sold in Monday’s move.

After the sell-off, the yen’s value dipped to a level not seen in nearly three months. But even at 79 against the dollar, the currency was still stronger than most Japanese companies had expected; in making plans for 2011, they had predicted the yen would be valued in the low 80s against the dollar.

Japan earlier this month introduced a series of subsidies for businesses hard-hit by the yen’s appreciation. The help includes reduced interest rates on loans and incentives to hire new employees. The government also set aside more than $6 billion to subsidize companies that are essential to the supply chain.

Business owners, Prime Minister Yoshihiko Noda said Friday, “are gritting their teeth in an effort to maintain operations in Japan.”

“If large corporations relocate their bases overseas,” he said, “the small and medium enterprises that are their business partners would be obliged to follow, making it a real possibility that precious places of employment that would normally remain in Japan will be lost.”