REFILE-China stocks jump 4.5 pct, 2nd biggest gain this yr

(Corrects day of week in lead to Thursday from Wednesday)

SHANGHAI Aug 20 (Reuters) - Chinese stocks jumped 4.52 percent on Thursday, posting their second biggest daily percentage gain of the year, as modest signs of official support for the market helped to trigger technical buying after a 20-percent dive in the two weeks up to Wednesday's close.

The Shanghai Composite Index .SSEC closed at 2,911.582 points, after diving 4.3 percent on Wednesday.

Gaining Shanghai A shares outnumbered losers by 884 to 60, while turnover for Shanghai A shares was moderate at 121.7 billion yuan ($17.8 billion) against Wednesday's 121.9 billion yuan.

The rebound nudged the index just above the closely watched five-day moving average, now at 2,905 points. Analysts said a convincing move above that level could indicate the index had stabilised after the recent sell-off.

PetroChina (601857.SS), the most heavily weighted stock in the index, gained 6.85 percent to 13.88 yuan. ($1=6.83 Yuan) (Reporting by Claire Zhang and Edmund Klamann)