The Nikkei inched up 0.10 percent to stay above 18,000 on Wednesday as Marubeni Corp surged on news of its plan to invest in United Arab Emirates, but investors sold Advantest Corp and other recent gainers.
NEC Electronics Corp. jumped more than 8 percent after Macquarie upgraded the stock to "outperform" from "underperform".
"Shares in companies that have exposure to BRIC nations are targeted. They are about the only companies with strong profit prospects," said Tsuyoshi Nomaguchi, strategist at Daiwa Securities Co. Ltd, referring to such countries as Brazil, Russia, India and China (BRICs).
"The Nikkei is firmly above 18,000 and this indicates that people in the market see there is upside potential," he added.
The Nikkei added 18.89 points to 18,072.70 as of 0433 GMT, while the broader TOPIX index rose 0.24 percent to 1,780.78.
Marubeni leapt 9.1 percent to 974 yen after the Nikkei business daily highlighted Marubeni's investment plan in the United Arab Emirates. Reuters reported in April that an alliance of Britain's International Power and Marubeni made the lowest bid in a $3 billion seawater desalination and power project in the UAE.
Gains in Marubeni also helped its peers with Itochu Corp up 3.3 percent and Mitsui & Co. Ltd. adding 1.4 percent.
Investors also flocked to Komatsu Ltd, the world's second largest maker of construction machinery, for its exposure to China and other emerging markets. The stock rose 3 percent to 3,440 yen, its all-time high.
Among stocks that were sold, Advantest lost 0.7 percent to 5,360 yen, snapping its four-day winning streak. Likewise, Canon Inc shed 0.4 percent to 7,160 yen after hitting this year's high of 7,280 yen on Monday.
Shares of Rakuten Inc., an online shopping mall operator, fell 1.9 percent to 39,850 yen after Japan's financial market watchdog called for disciplinary action against its brokerage unit for recurring system problems.