TOKYO: Japan's Nikkei index inched higher in choppy trade on Thursday, boosted by transport shares and Wall Street's overnight jump, although the gains were capped by uncertainties around the COVID-19 pandemic.

The Nikkei share average was up 0.04% to 27,734.63 by 0144 GMT, while the broader Topix edged down 0.09% to 1,933.88.

"Japan's market is supported by the US shares, which was driven by expectations for an economic expansion. That is boosting stocks of airlines and railways today," said Shoichi Arisawa, general manager of investment research at IwaiCosmo Securities.

The three major US indexes ended the session modestly higher overnight, with the S&P 500 and the Nasdaq to record closing highs.

"But, there have been strengthened uncertainties around several factors, including the directions of the pandemic and its impact on the supply chain systems in South East Asia, as well as the US interest rates."

Airlines gained 2.3%, the most among the Tokyo Stock Exchange's 33 industry subindexes, with Japan Airlines and ANA Holdings rising 2.51% and 2.06%, respectively.

Railways rose 0.78%, with Central Japan Railway , which runs bullet trains between Tokyo and Osaka, gaining 0.78%. Tokyo-based East Japan Railway rose 0.93%.

Chip-related stocks Sumco Corp added 3.13%, while Tokyo Electron and Advantest rose 2.3% and 2.45%, respectively.

Toshiba edged up 0.97% after a report that Western Digital is in advanced talks for a potential $20 billion stock merger with Japanese semiconductor firm Kioxia Holdings Corp, of which Toshiba owns 40.5%.

Seven & i Holdings lost the most among the Topix 30, down 3.02%, followed by Sony Group Corp that lost 1.88%.