Official rule text
16.3 If a player has more fighters and ground forces in the space that player cannot capture units from the blockading players. area of a system than the total capacity of that player’s ships in that system, that player must remove the excess units. RELATED TOPICS: Blockaded, Fighter Tokens, Ground Combat, Infantry Tokens, Space Combat, When a player gains a command token, they choose which of 18 COMBAT (ATTRIBUTE) 20.2 their three pools to place it in. Combat is an attribute of some units that is presented on faction
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Source: Twilight Imperium: Fourth Edition - Living Rules Reference: Prophecy of Kings
Expansion: Prophecy of Kings
Version: 2.0
Reference: Rule 16.3