Hearts of Iron IV is a grand strategy game released by Paradox Interactive in 2016, set during the Second World War. Its convoy system handles overseas movement of troops, equipment and resources, and the transport sound became familiar through thousands of hours of campaigns and multiplayer sessions. As HOI4 clips spread on YouTube, Twitch and Discord, players began lifting the cue for edits outside the game, using it whenever an invasion, evacuation or supply run needed a recognisable strategy game stamp of approval.