X-Day (余命検索サービスX-DAY Life Expectancy Service X-Day?), stylized as X-DAY, is a quiz arcade game developed and released by Namco in 1993; it runs on Namco NA-1 hardware, and is one of the few NA-1-based arcade games to not be emulated in any form. The player must answer several questions regarding the overall health of his or herself, and the game will determine how long the player will live and when they will die. A sequel, X-Day 2, was released in 1995; it also ran on Namco NA-1 hardware, and focuses on how long the player has in a relationship with another. An online version of both games were made by Pro House in 1998, while a mobile phone version made by Namco was released for i-Mode and EZ Web in 2003.