The Sensex at the Bombay Stock Exchange gained 174 points, or 0.9 percent, to 18,805, today, on all-round buying, ahead of the release of some big corporate quarterly results. The Nifty at the National Stock Exchange rose 56 points, or 1 percent, to 5,708. But stock markets in Japan, China, and South Korea declined between 0.6 percent and 0.8 percent.