The Sensex opened over 200 points up today on bargain buying triggered by firming trend on other Asian bourses after yesterday's losses. The 30-share index of the Bombay Stock Exchange, which lost over 271 points in the previous session, rebounded by 200 points or 1.10 per cent to 18,368 level, with oil and gas, metals, realty and banking stocks, leading the recovery. Similarly, the wide-based National Stock Exchange Nifty index also moved up by 57.65 points or 1.05 per cent to 5,507 points. Meanwhile, Japan's Nikkei index was trading 4.43 per cent higher but Hong Kong's Hang Seng Index was down by 0.27 per cent in early trade today.