Japan's Nikkei notched a small decline on Tuesday, while the broader Topix was flat, as investors kept to the sidelines ahead of Wednesday's U.S. Federal Reserve meeting.

The Nikkei closed 0.16% lower, its second straight daily drop. Turnover, as on Monday, was light.

"Markets are definitely in a wait-and-see mode, what you're seeing is gentle position adjusting," said Jeffrey Halley at brokerage OANDA in Singapore, ahead of the Fed, U.S. growth data and a slew of U.S. earnings. "It's the calm before the storm."

Tech investor SoftBank Group Corp rose 3.2% - its biggest daily gain in about a month - after Hong Kong shares rose for one of its holdings, Chinese tech giant Alibaba . Alibaba plans to add a primary listing in Hong Kong.

Other gainers included insurer Tokyo Marine Holdings Inc , up 1.6%, engineering firm JGC Holdings, and oil and gas exporter Inpex, up 3.3%. Supply concerns in Europe are lifting global energy and gas prices.

Japan also upgraded its overall view on the economy for the first time in three months in July, with the government turning more positive on consumption and jobs.

Minutes from last month's Bank of Japan meeting underscored policymakers resolve to keep interest rates low.

Underperformers among the Topix 30 were Nidec Corp, down 1.57%, followed by Nintendo Co Ltd, losing 1.20%.

The dollar traded firmly at 136.68 yen. Traders expect a 75 basis point U.S. rate hike on Wednesday, but there are doubts around the future path for rates amid signs of a few wobbles in the U.S. economy.

The volume of shares traded on the Tokyo Stock Exchange's main board was 0.91 billion, compared to the average of 1.21 billion in the past 30 days. (Reporting by Tom Westbrook and Vidya Ranganathan in Singapore; Additional reporting by Junko Fujita in Tokyo; Editing by David Holmes)