TOKYO, Aug 18 (Reuters) - Japan's Nikkei ended flat on Monday in thin trade as geopolitical tensions dulled risk appetite, but Chugai Pharmaceutical jumped on a media report that Roche Holding AG's may be close to sealing a deal to take full ownership of the Japanese drugmaker.
The Nikkei was flat at 15,322.60 in choppy trade.
Global markets are also closely focused on this week's annual meeting of top central bankers and economists in Jackson Hole, Wyoming.
A total of 1.54 billion shares changed hands, the least since mid-April.
The broader Topix edged up 0.1 percent to 1,271.26, and the new JPX-Nikkei Index 400 was flat at 11,564.70.
(Editing by Shri Navaratnam and Eric Meijer)