The Sensex at the Bombay Stock Exchange gained 52 points, or 0.3 percent, to close at 18,814, today, amid rising Asian markets. The Nifty at the National Stock Exchange added 23 points, or 0.4 percent, to 5,651. Stock markets in Japan, China, Hong Kong, South Korea, and Singapore rose between 0.5 percent and 2 percent.