TOKYO, Dec 21 (Reuters) - Japanese shares fell from a 29-1/2-year high hit earlier in the session on Monday, as concerns about a spike in domestic coronavirus infections and the emergence of a new strain of the virus in Britain weighed on sentiment for riskier assets. The Nikkei 225 Index fell 0.64% to 26,592.82 by 0212 GMT. At the opening bell, the benchmark rose to its highest level since April 1991 but quickly erased those gains and headed lower. The broader Topix also fell 0.67% to 1,781.20. New coronavirus infections have been rising to record levels in Tokyo and other major cities. European countries are blocking travel from Britain after a new strain of coronavirus was identified that is up to 70% more infectious. Sentiment also took a hit due to faltering trade negotiations between Britain and the European Union, while some analysts pointed to a rising yen as a reason to sell shares in Japanese exporters. The combination of negative factors suggests that Tokyo shares will likely end 2020 on the back foot, after rallying 64% from this year’s lows in March. “Some investors are worried that stocks have been overbought, so it is tempting to book profits in reaction to negative news about the coronavirus,” said Kiyoshi Ishigane, chief fund manager at Mitsubishi UFJ Kokusai Asset Management. The underperformers among the Topix 30 were Fanuc Corp down 2.40%, followed by Honda Motor Co Ltd losing 2.33%. The top gainers on the Topix 30 index were Daikin Industries Ltd, up 2.23 %, followed by Mitsubishi UFJ Financial Group Inc, gaining 1.52%. There were 39 advancers on the Nikkei index against 182 decliners. The volume of shares traded on the Tokyo Stock Exchange’s main board was 0.5 billion, compared to the average of 1.34 billion in the past 30 days. (Reporting by Stanley White; Editing by Rashmi Aich)