Living Rules Reference · v2.0
60
Neighbors
Two players are neighbors if they both have a unit or control a planet in the same system. They are also neighbors if they both have a unit or control a planet in systems that are adjacent to each other.
Players can resolve transactions with their neighbors.
Players are neighbors if the adjacency of systems is granted by a wormhole.
Players are neighbors with the Ghosts of Creuss if the Ghosts of Creuss’ “Quantum Entanglement” faction ability is causing adjacency from the perspective of the Ghosts of Creuss player.
Source: Twilight Imperium: Fourth Edition — Living Rules Reference v2.0 (September 22, 2020), page 24. Rules text reproduced verbatim; the rulebook’s diagrams are omitted.