The benefits of the Trans-Pacific Partnership — for which a broad agreement was finally clinched this week by 12 Pacific Rim countries, including Japan and the United States — should not be overblown. Rather, a sober assessment is needed of what Japan stands to gain or lose from a pact that, once in effect, eliminates or cuts import tariffs and sets common rules on a broad range of areas, such as investment and handling of intellectual property among countries that together account for nearly 40 percent of the global economy.

The conclusion of the TPP negotiations, which had been marred by lingering disagreements among the participants that repeatedly threatened to cast the talks adrift, may come as a political victory for Prime Minister Shinzo Abe, who not only positioned the free trade pact as a major component of his strategy to fuel Japanese economic growth but viewed it as a key to solidifying relations with Washington — along with beefing up the security alliance with the U.S. — in the face of China's growing presence in both the economic and regional security landscape.

But the Abe administration still needs to explain details of the TPP deal and its impact on Japan's economy and people's lives — to the public and the Diet when seeking its ratification — a job that will be particularly important since much of the negotiations were shrouded in secrecy.