The Bombay Stock Exchange benchmark Sensex on Monday opened over 170 points up at 19,755. The sensex was trading at 207 points up at 19,793 a short while ago.The rise in sensex is on emergence of bargain buying by funds and investors in blue chip companies amid strong Asian cues.In Asian markets, the Hong Kong's Hang Seng Index was marginally down by 0.29 per cent while the Japanese Nikkei gained 1.10 per cent in the morning trade.