The revolt was led by Guo Huaiyi , a sugarcane farmer and militia leader originally from Quanzhou known to the Dutch by the name Gouqua Faijit, or Gouqua Faet. After his planning for an insurrection on 17 September 1652 was leaked to the Dutch authorities, he decided to waste no time in attacking Fort Provintia, which at the time was only surrounded by a bamboo wall. On the night of 7 September the rebels, mostly peasants-farmers armed with bamboo spears, stormed the fort. The following morning a company of 120 Dutch musketeers came to the rescue of their trapped countrymen, firing steadily into the besieging rebel forces and breaking them. Governor Nicolas Verburg On September 11 the Dutch learned that the rebels had massed just north of the principal Dutch settlement of Tayouan. Sending a large force of Dutch soldiers and aboriginal warriors, they met the rebels that day in battle and emerged victorious, mainly due to the superior weaponry of the Europeans. Multiple Aboriginal villages in frontier areas rebelled against the Dutch in the 1650s due to oppression like when the Dutch ordered aboriginal women for sex, deer pelts, and rice be given to them from aborigines in the Taipei basin in Wu-lao-wan village which sparked a rebellion in December 1652 at the same time as the Chinese rebellion. The Wu-lao-wan beheaded two Dutch translators, and in a subsequent fight with 30 Wu-lao-wan two Dutch people died, but after an embargo of salt and iron the Wu-lao-wan were forced to sue for peace in February 1653.
Question: How many days before Guo's planned insurrection did the rebels attack the fort?
Answer: 10