TI4 Rules DeskTwilight Imperium 4
Living Rules Reference · v2.0
14

Blockaded

Marked text is printed in red in LRR v2.0 (new or changed with Prophecy of Kings)

A player’s unit with “Production” is blockaded if it is in a system that does not contain any of their ships and contains other players’ ships.

A player cannot use a blockaded unit to produce ships; that player can still use a blockaded unit to produce ground forces.
When a player blockades another player’s space dock, if the blockaded player has captured any of the blockading player’s units, those units are returned to the blockading player’s reinforcements.
  1. While a player is blockading another player, the blockaded player cannot capture any of the blockading player’s units.

Source: Twilight Imperium: Fourth Edition — Living Rules Reference v2.0 (September 22, 2020), page 11. Rules text reproduced verbatim; the rulebook’s diagrams are omitted.