After a long period of repression by the Dutch colonial government, ethnic Chinese in Batavia  revolted on 7 October 1740, killing fifty Dutch troops in Meester Cornelis  and Tanah Abang. This revolt was quashed by Governor-General Adriaan Valckenier, who sent 1,800 troops, together with schutterij  and eleven battalions of conscripts, to the two areas; they imposed a curfew on all Chinese inside the city walls to prevent them from plotting against the Dutch. When a group of 10,000 ethnic Chinese from nearby Tangerang and Bekasi was stopped at the gates the following day, Valckenier called an emergency meeting of the council for 9 October. The day of the meeting, the Dutch and other ethnic groups in Batavia began to kill all ethnic Chinese in the city, resulting in an estimated 10,000 deaths over two weeks. Towards the end of October 1740, survivors of the massacre, led by Khe Pandjang, attempted to flee to Banten but were blocked by 3,000 of its sultan's troops.  The survivors then fled east, towards Semarang.  Despite being warned of an imminent uprising by Chinese Lieutenant Que Yonko, the military commander for Java, Bartholomeus Visscher, dismissed the threat of the incoming Chinese. A minority in Java, the Chinese began forging alliances with the Javanese, who were the largest ethnic group on the island. Adoption of Islam back then was a marker of peranakan status which it no longer means. The Semaran Adipati and the Jayaningrat families were of Chinese origin.
Question: When did the killing of ethnic Chinese begin?
Answer: 9 October 1740