The Bombay Stock Exchange benchmark Sensex on Monday opened 233 points higher on buying by funds, which took cues from firm global markets. The 30-share index shot up by 233.60, or 1.33 per cent, to 17,804.42 points in the first five minutes of trading. Similarly, the wide-based National Stock Exchange index Nifty moved up by 66.00 points, or 1.25 per cent, to 5,328.60 points. Brokers said trading sentiment turned better as Asian bourses opened higher after China decided to increase the yuan's flexibility. Japan's Nikkei gained 1.77 per cent and Hong Kong's Hang Seng index was up 1.91 per cent in the morning trade.