Shinjuku Station is one of the busiest railway stations in the world, serving millions of passengers on JR East lines in central Tokyo. The doors-closing warning is a familiar part of daily commuting there, combining a short melodic chime with a recorded announcement to alert passengers before departure. Clips of the sound have become popular online with creators making travel vlogs, Japan guides and transit edits, because it immediately signals Tokyo and train travel without any explanation. Its recognisable rhythm keeps it useful for scene-setting years after it was first recorded.