Chinese sharemarkets (like the Shanghai and Shenzen exchanges) were closed today due to the circuit breaker.
A 15-minute halt to trading is triggered if the CSI300 (this is an index that tracks the 300 largest shares in the country, these trade on Shanghai or Shenzen exchanges) dips 5%
Trading is completely halted for remainder of the session if the index falls 7%
That's the theoretical way it works.
I'll try to find a practical example. Yes, that's a joke.
Trade was halted today within 30 minutes of the opening after the CSI300 fell the required 7%. Actual trading time was only 14 minutes, as trade halted for 15 minutes once the index fell 5%.
Today was the shortest trading session in China's stock market 25 year history.
The final score: