TOKYO » Rakuten is not just the top shopping website in Japan. These days the company is doing some serious shopping of its own as it turns the strong yen — usually seen as a huge negative for Japanese companies — into a plus.

The online shopping mall operator has bought several overseas businesses in the last year and is not the only Japanese company on an acquisition spree. Businesses from pharmaceutical companies to toy makers have been emboldened by the increased purchasing power that the rising yen gives them.

A strong yen has long been characterized as potentially fatal for Japan Inc. by making the country’s cars, consumer electronics and other goods more expensive abroad, eating into the earnings of giant exporters like Toyota Motor Corp., Sony Corp. and Nintendo Co.

But for a service company such as Rakuten Inc., the yen at post World War II highs is a boon it hopes will help it catch up to giants in the global e-commerce hierarchy such Amazon and eBay. The yen is up nearly 8 percent against the U.S. dollar over the past year.

"I like it," Rakuten Chief Executive Hiroshi Mikitani said with a grin when asked about the yen’s gains. "We can buy more companies."

Mikitani also thinks Japan’s traditional export-focused manufacturers should be taking advantage of the yen’s rise by buying rivals in emerging markets. But he said some may be reticent as they lack the management expertise to know what to buy or how to make it work.

"They should think about that, and utilize the strength of the currency as a weapon," Mikitani told reporters. "I think we should favor the stronger yen."

Embracing a strong yen is an uncommon attitude among Japanese CEOs, and officials. Rakuten is different in other ways too. Nearly three quarters of the hires joining the company this month were foreigners and Mikitani’s pep talk at a welcoming ceremony this week was in English, the standard language at Rakuten — both rarities for usually insular Japanese companies.

The jump in overseas acquisitions by Japanese companies this year has come even though the global economy faces extremely uncertain times and Japan’s own economy has reeled from the March 11 earthquake and tsunami disasters.

Data compiled by Tokyo-based Recof Corp., which advises on acquisitions, found overseas takeovers and acquisitions by Japanese companies gained by 30 percent in number of deals in the first eight months of this year.

The jump was most pronounced in Asia, where the number of deals increased 50 percent year-on-year to 143, a record for the region, although the purchase prices were bigger for deals in the U.S., according to Recof.

Data from Dealogic shows that the value of overseas takeovers and acquisitions by Japanese companies in January through August more than doubled from a year earlier to $46.7 billion.

Among the biggest Japanese takeovers announced in recent months was Takeda Pharmaceutical Co.’s deal to buy Switzerland’s Nycomed for $13.6 billion, giving Japan’s biggest drugmaker coveted access to emerging markets.

Another was Tomy Corp.’s purchase of RC2, the U.S. maker of Chuggington and Thomas & Friends toys in an all-cash deal valued at about $640 million.

Online securities company Monex Group Inc. bought TradeStation Group, based in Florida, in a deal valued at up to $411 million. Brewers such as Kirin and Asahi have also been busy acquirers.

The yen’s gains can also tip the scales in favor of manufacturing investments overseas.

Last month, Honda Motor Co. announced a $50 million investment to boost transmission production in the U.S., bringing the automaker’s capital investment in Ohio to more than $400 million for this year.

Matt McCollister, a vice president at central Ohio’s economic development panel, Columbus2020, said the strong yen came up often in meetings with Japanese executives as a solid incentive for overseas investment. He visited Japan recently to woo more investment to the state.

"I don’t know that it’s the primary catalyst, but it can definitely be a tipping point for a project, especially if there’s one that has been under consideration," he said. "When you start to apply the currency differential, it may make more financial sense than it did a year ago."

Still, there is no doubt that the yen’s unrelenting strength is the source of plenty of woe for many of the Japanese corporations that are global household names. It has also added to worries in Japan that more manufacturing could be shifted overseas, hollowing out industry and jobs.

Like other Japanese automakers, Honda has been hit hard. It says the yen erased 22.5 billion yen ($288 million) from its April-June operating profit. The Tokyo-based maker of the Odyssey minivan and Accord sedan had initially counted on the dollar trading at 80 yen this fiscal year through March 2012. The dollar is now hovering between 76 yen to 77 yen.

The automaker has been moving production to the markets where vehicles are sold. For the more specialized cars still being exported from Japan, pressure is on to cut costs to make the business worthwhile, sometimes delaying model launches until such cuts are achieved, Honda officials say.

Squeezing positives out of a strong yen is a change of pace for Japan which has been, up to now, obsessed with trying to prop up the dollar to protect its exporting giants.

Such efforts have proved largely futile in recent years against larger global developments that nowadays include the debt crisis in Europe and fears of another recession in the U.S.

Japan’s finance ministry most recently tried to weaken the yen in August, by buying dollars. That did send the yen lower but the effect lasted only days.

For Rakuten, a robust yen is key to its ambitions to one day become the world’s No. 1 e-commerce company.

In September, Rakuten announced an agreement to buy British e-commerce site Play.com for 25 million pounds (3.3 billion yen, $43 million), following the acquisition of PriceMinister of France and German online shopping mall Tradoria.

The moves add to an empire that now sprawls across 10 countries, including Japan, raking in 90.7 billion yen ($1.2 billion) in April-June sales, a quarterly record for Rakuten. Its business also includes Buy.com of the U.S. and a partnership with Baidu Inc. in China as well as ventures in Thailand, Russia, Taiwan and Indonesia.

Kevin M. Carroll, who runs EA International, an environmental engineering and consultancy company in Tokyo, says the shrinking Japanese population and the high labor costs as well as corporate taxes in Japan are making overseas growth even more crucial for Japanese companies.

The days when a big Japanese corporation could prosper just by catering to customers in Japan are long over, said Carroll.

"The strength of the yen in most foreign markets works for Japanese companies as it places them in the envious position of acquiring foreign firms or technologies at a discount," he said.