Nine Hours, Nine Persons, Nine Doors (later re-released as Zero Escape - Nine Hours, Nine Persons, Nine Doors, known as as Kyokugen Dasshutsu 9 Jikan 9 nin 9 no Tobira in Japan) is an adventure game developed by Chunsoft and published by Aksys Games (in North America) and SPike (in Japan). It was also released for iOS. An updated version with voice acting and HD graphics was released as part of a compilation for PS Vita, Playstation 4, PC and Xbox One.

The protagonist is Junpei, a college student. One evening, he comes back to his room to find a figure in dark cloak wearing a gas mask. Before he can react, sleeping gas fills the room and he falls unconscious. When he wakes up, he finds himself inside a ship's cabin, and before long, the window bursts and water starts pouring in. After managing to escape, Junpei meets eight other people who, as it turns out, were also kidnapped by the same person the same way, and borught to this ship. Their mysterious kidnapper then welcomes them via a speaker. They all have been chosen to be part of a game he calls Nonary game. They have 9 hours to escape the ship, which is sinking, by finding and opening a door with a 9 written on it. As they soon find out, they will have to pass lethal challenges, and their host has made sure that not sticking to the rules he set up will result in immediate death.

The game is a visual novel with small puzzle sections. During the visual novel sections, you occasionally make decesions which will have an effect on the story and the ending of the game. The puzzle section are escape-the-room scenarios where you need to find a way to unlock the door to your further path. You seach a small number of rooms in Myst-style first-person while solving both logic puzzles and object-based adventure game puzzles.