Firm start on strong global cues but China stocks down 4%: The market opened higher but soon flattened out quickly within minutes. The F&O expiry later this week could bring in some choppiness. Indices could swing later in the day after a run-up for seven days in a row. China stocks continued its falling streak and fell over 4 per cent in intraday trade. It had slumped more than 13 per cent last week. Japan's Nikkei rose to a fresh 15-year high and was trading above 20,700.