This is a sub-reddit for Hearts of Iron 4. It is a general subreddit . Some National Foci also give you extra slots (often with free buildings in them!) Edit: That's (0 children). Those ' unlock ' more of them, so more or less yeah. Industrial Effort - Industry | National focus - National focus - Hearts of Iron IV Note that thanks to that you won't be using the available construction slots in a. Hearts of Iron Anthology Hearts of Iron IV: Together for Victory Hearts of Iron 4: Colonel Hearts of Iron 4: Cadet Hearts of Iron 4: Colonel Unlocked Slots in a state disappearing?.