The aim of the game is for the "finders" to find the "hider" by asking a series of yes/no questions. These may relate either to the hider's current location or to his/her previous route. A maximum of two questions in a row per player is permitted. There is no limit to the total number of questions allowed. The winner is the player who correctly identifies the hider's current location.
If a player asks a question before the previous question has been answered, the hider should answer as though it had been asked after that question was answered, even if a move intervenes.
Rules regarding movement:
1) The hider can start at any station on one of the following networks: London Underground, London Overground, DLR, TfL Rail.
2) After each even-numbered question, the hider must make a move of one stop on any of the above networks in any permitted direction (except as under rule 5/6). The hider may not move after odd-numbered questions.
3) The hider can change line only where two lines intersect in the same station, with this defined by Guinness rules, i.e. no switching between:
- The two Paddingtons, Edgware Roads or Hammersmiths
- Bank and Monument
- Shadwell (LO) and Shadwell (DLR)
- Shepherd's Bush (LO) and Shepherd's Bush (LU)
- West Hampstead (LO) and West Hampstead (LU)
- Liverpool Street (LU) and Liverpool Street (LO/TfL Rail)
- Any marked interchange between two differently named stations
- Any interchange not shown is between two separate stations (e.g. Canary Wharfs, Eustons etc.)
5) If it becomes impossible for the hider to move any more, he/she must say so and remain in the same location for the rest of the game.
6) The hider may choose to come to a halt at any time. If this is the case, he/she must say so and remain in the same location for the rest of the game.
7) Station specific rules:
- Heathrow Loop is one way only
- Tottenham Court Road is Northern Line only (temporarily)
- Tufnell Park is nonexistent (temporarily)