TOKYO — Japan said Thursday that it had intervened in the foreign exchange market, selling yen and buying dollars in a bid to reverse a punishing spike in the value of the Japanese currency.

Japan has been desperate to bulwark its fragile recovery from the March earthquake and tsunami. But even as companies have raced to repair damaged factories and resume production, they have been hit by a surge in the yen that threatens their business overseas.

A strong yen hurts Japan’s export-led economy by making its cars and electronics more expensive overseas, and by eroding the value of overseas earnings when converted into yen.

But the Japanese currency, long considered a safe haven, rose as investors wary of the debt impasse in the United States fled to other currencies. Against the dollar, the yen has surged about 11 percent in the last year, and 4 percent in the last month.

The rise has accelerated an upward trend in the yen that was already squeezing Japanese exporters’ profits. Toyota, Honda and Nissan all recently blamed their sharply lower earnings in the latest quarter in part on the strong yen.

Still, the effect of moves to manipulate foreign exchange markets, especially by a single country, has often been short-lived. Japan acted alone in the intervention on Thursday morning, though Tokyo is in touch with other countries over the maneuver, Yoshihiko Noda, its finance minister, told reporters. He also said he hoped that the Bank of Japan would take steps to support the government’s move.

The Bank of Japan, which has had a sometimes troubled relationship with the government, appeared to support the intervention. The central bank said Thursday morning it would end its regular policy meeting a day early, a sign it could announce additional policy to support the government’s bid to weaken the yen.

In a note to clients, Masaaki Kanno, an economist at JPMorgan Securities, said he expected the bank to announce a further easing of Japan’s monetary policy by extending an asset purchase program that would increase the bank’s reserves, increasing liquidity and helping to dilute the value of the yen.

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