TI4 Rules DeskTwilight Imperium 4
Living Rules Reference · v2.0
39

Game Board

The game board consists of all system tiles in play.

The game board consists of all system tiles that were placed during setup, even if the sides of those tiles do not touch any other system tiles, such as the Ghosts of Creuss’ home system.
A system tile is on the edge of the game board if any of its sides are not touching another system tile.
  1. The Ghosts of Creuss home system and the wormhole nexus are on the edge of the game board.

Source: Twilight Imperium: Fourth Edition — Living Rules Reference v2.0 (September 22, 2020), page 19. Rules text reproduced verbatim; the rulebook’s diagrams are omitted.