The weak yen may have come too late to convince manufacturers to keep production in Japan, with Carlos Ghosn, Nissan Motor's CEO saying the company will stick with its plans to localize its auto plants.
"[The] strategy that we have maintained for the past years, which consists of localizing production as much as possible, will continue," Ghosn told CNBC, adding Nissan plans more investments in North America, China and Southeast Asia.
"We don't want to fall into this trap in the future of depending on the situation of the exchange rate to have a huge impact on our profitability," he said.
(Read more: Nissan to build self-driven cars)
Indeed, the yen's current level can only be viewed as "neutral," he noted. "It's not an advantage. It's not a present. At the same time, it's not the handicap that it used to be when it was between 80 and 90 yen to the dollar."
In April, the Bank of Japan surprised the markets with an unprecedented surge of easing measures, which weakened the yen from around 90 to the U.S. dollar to the current levels around 100.
Ghosn still considers Japan an important export base, but the focus will change. "It will mainly be an export base for cars with very small numbers sold, which will not justify the duplication of the investment," such as niche or extremely high-end products, he said. Japan will also be an export base for countries with no manufacturing base, he added.
Japanese companies have been boosting investment in their overseas affiliates.
(Read more: General Motors plans pullout from South Korea)
For the fiscal year ended March 31, 2012, the latest available data, capital investment in overseas affiliates by Japanese manufacturers rose 32.5 percent on-year; among companies responding to the survey for both years it was up 19.6 percent. Companies' ratio of production overseas was fairly steady for the period, although it varied widely by industry.
But a better indication may come from foreign direct investment by Japanese residents, noted Marcel Thielant, an economist at Capital Economics. For the year through July 2013, it reached a record high of 2.8 percent of gross domestic product, indicating companies are continuing to shift production overseas, he said via email, noting July's outflow was the highest on record.
"There are clearly no signs that the weak yen has encouraged producers to stop shifting production abroad," he said.
(Read more: Parity a mirage for the yen)
To be sure, not everyone is certain Japan Inc. is relocating overseas.
"Clearly a lot of companies still make a lot of things in Japan. It's still a heavily industrialized nation," said Mark Matthews, head of research for Asia at Julius Baer; he noted most of Toyota's production is still in Japan.
While many Japanese companies have plans to move production, "I think now they're reassessing those plans," he said, noting he knows of one major conglomerate that has indicated as much.