The Sensex at the Bombay Stock Exchange rose a modest 29 points, or 0.2 percent, to close at 18,865, on value-buying by investors on Monday.The Nifty at the National Stock Exchange gained 22 points, or 0.4 percent, to 5,704.But stock markets in Japan, China and South Korea declined between 0.1 percent and 2.1 percent.