Snapping a four-day losing streak, the Sensex at the Bombay Stock Exchange shot up 407 points–its biggest single-day gain in nearly two months–to close at 18,313, on value-buying in blue-chips, and amid rising European markets,on thursday. The Sensex had lost over 1,400 points in the past four trading sessions. The Nifty at the National Stock Exchange spurted 106 points, or 2 percent, to 5,408.But stock markets in Japan, China, South Korea and Singapore declined between 0.3 percent and 1 percent.