Quoc: The first and second drafts of the pilot script by Benioff and Weiss were submitted in August 2007 and June 2008, respectively. Although HBO liked both drafts, a pilot was not ordered until November 2008; the 2007 -- 2008 Writers Guild of America strike may have delayed the process. The pilot episode, "Winter Is Coming", was first shot in 2009; after a poor reception in a private viewing, HBO demanded an extensive re-shoot (about 90 percent of the episode, with cast and directorial changes).

When did they start filming game of thrones?
HW Chung: OK, some thoughts:
The relevant sentence in the passage is: The pilot episode, "Winter Is Coming", was first shot in 2009; after a poor reception in a private viewing, HBO demanded an extensive re-shoot (about 90 percent of the episode, with cast and directorial changes). The answer is 2009.