TOKYO, Dec 16 (Reuters) -Japan's Nikkei was flat on Thursday as optimism after the dollar hit a near three-month high against the yen the previous day was offset by worries over euro zone debt and overheating in the market.
The Nikkei has been trapped in a narrow range this week as domestic investors aggressively took profits on its rally of around 12.6 percent since the beginning of November, while foreign investors continued buying financial shares seen as undervalued.
The Nikkei was flat at 10,307.56 in early trade. The broader Topix index lost 0.05 percent to 902.02. (Reporting by Antoni Slodkowski; Editing by Joseph Radford)