Filming this episode required 55 nights of filming over 11 weeks, and an unknown number of day shoots on stages, with roughly 750 cast and crew members. It was also a moving shoot that had to adjust with the moon. Several actors described this episode as the hardest thing they ever filmed. Maisie Williams (Arya) stated in Entertainment Weekly, "Nothing can prepare you for how physically draining it is. It's night after night, and again and again, and it just doesn't stop. You can't get sick, and you have to look out for yourself because there's so much to do that nobody else can do... there are moments you're just broken as a human and just want to cry." Iain Glen (Jorah Mormont) described it as a "real test, really miserable. You get to sleep at seven in the morning and when you wake in the midday you are still so spent you can't really do anything, and then you're back. You have no life outside it." Rory McCann (The Hound) concurred: "Everybody prays they never have to do this again." Glenn did add that it was only worse for the crew, since unlike the actors, they had to be on set at all times.
After filming a key scene from the episode, the crew was interrupted by a helicopter flying overhead, even though the production was supposed to have government-protected airspace across the sets: no planes, no drones, and no paparazzi whatsoever. The production called the Civil Aviation Authority to track down the pilot's identity, while production was in a "panic" that spoilers would leak from the set, but eventually it turned out to be a police helicopter.
With Jaime and Brienne fighting side-by-side, their swords Widow's Wail and Oathkeeper, the two halves of Ned Stark's Valyrian steel sword Ice, are reunited to protect Winterfell, the Starks' stronghold.
David Benioff and D.B. Weiss told Entertainment Weekly, prior to the airing of season 8, that they already knew back in 2013 that the final season would have to be significantly shorter than regular seasons, knowing the planned sequences for the final episodes would require much more budget than HBO could offer to give them, naming this episode in particular as one of the main examples.
While writing the episode, showrunners D.B. Weiss and David Benioff intended this to be the longest battle sequence ever presented in a film or television, with the largest number of extras fighting on a real location, and avoiding the use of CGI as much as possible. While preparing for the shoot, director Miguel Sapochnik tried to find a longer battle sequence in cinema and couldn't. The closest Sapochnik found was the 40-minute Battle of Helm's Deep in The Lord of the Rings: The Two Towers (2002), which he studied to determine when and if the audience would get "battle fatigue" from too much meaningless action. Ironically, his conclusion was that "the less fighting you can have in a [specific] sequence, the better."