Japan's entry into the Trans-Pacific Partnership free-trade negotiations has significantly boosted the economic scale of the envisioned pact, but it has also brought new complexity to the multilateral talks that have been strongly influenced by the world's leading economy, the United States.
With Japan, which has the world's third-largest economy, having made its belated debut as the 12th member near the end of the talks' 18th round, TPP countries now account for nearly 40 percent of the world's gross domestic product and about one-third of total world trade.
"As the countries see significance in terms of trade and economy, Japan's entry was very much welcomed," said Koji Tsuruoka, the country's chief negotiator after the latest round wrapped up Thursday in Malaysia.