Un is the final game of the first session, and those who survive are allowed to exit their Cube and return home.
Un is completely based on luck-on the way out, everyone who came with Urashima Tarou draws a rod with either a circle or an "x" on it, similar to right or wrong. Those who draw a circle live, those who draw the "x" are killed.
In the StoryEdit
After the end of dining and party games with Urashima, he has everyone draw from a box. Urashima then explains that, while the previous tests were based on intelligence, strength and creativity, the final test would be luck, or "Un". His head then raises to reveal an unspecified weapon, which then kills Shouko, Eji, Kotarou, and the older Sanada twin simutaniously, announcing Shun, Akimoto, Kris, Amaya and Yukio as the survivors.