The CSI300 index rose 0.1 percent, to 3,908.14 points at the end of the morning session, while the Shanghai Composite Index lost 0.2 percent, to 3,382.66 points.

Wu Kan, head of equity trading at Shanshan Finance, expected little market volatility before and during China's 19th Communist Party Congress, which will open on Oct. 18. China's securities regulators have said maintaining market stability is a major political task during the period.

"There's a lot of expectation that the government will accelerate state-owned enterprise (SOE) reforms," Wu said, explaining why defence-related stocks, most of which are state-owned, surged on Thursday.

The jump in the sector, which includes Avic Aviation High-Technology Co and China Spacesat Co , also appeared to be triggered by news that a U.S. Navy destroyer sailed near islands claimed by China in the South China Sea on Tuesday.

Chinese suppliers of military equipment and technology typically rise amid heightened geo-political tensions.

Energy and commodity shares fell. Shares in top coke producer Shanxi Coking slumped nearly 10 percent to six-week lows, after an announcement that it planned to slash output of coke and some chemical products as part of Beijing's campaign against air pollution, especially over the winter.

Meanwhile, investors combed through a flood of earnings reports from companies including Aier Eye Hospital, Liuzhou Iron & Steel and China Yangtze Power as they assess the health of China's economy.

HONG KONG

Hong Kong stocks were bolstered by strength in world equity markets which took heart from signs of global economic recovery, and after the U.S. Federal Reserve appeared to take a guarded view on inflation.

The Hang Seng index added 0.3 percent to hit 28,464.71 points, while the Hong Kong China Enterprises Index gained 0.8 percent to reach 11,501.05.

Financial and property shares rose but energy stocks sagged.

(Reporting by Samuel Shen and John Ruwitch; Editing by Eric Meijer)