The Sensex at the Bombay Stock Exchange posted a good gain of 173 points, or 1 percent, to 17,614, on revival of monsoon rains, and amid firm global markets, today. The Nifty at the National Stock Exchange rose 53 points, or 1 percent, to 5,289. Stock markets in Japan, China, Hong Kong, South Korea, and Singapore gained between 0.5 percent and 2 percent.