This expansion for Hearts of Iron IV adds dedicated national focus trees to the minor powers around the Black Sea and the Aegean. Bulgaria, Greece and Turkey can each chart unique historical and alternate history paths as they resist efforts by the major powers to dominate the strategic sealanes of the Bosporus and Dardanelles.

Features of Hearts of Iron IV: Battle for the Bosporus include:

• National Focus Tree for Bulgaria: Balance the factions in a divided land or reclaim territory lost in 1919. Follow the historical alliance with Germany or resist the German pressures on Tsar Boris, standing up for a free Bulgaria.
  
• National Focus Tree for Greece: Riven by political division, Greek neutrality is maintained by the controversial Metaxas. Build a strong relationship with the Allies under the guidance of King George II, follow arch-conservatives into fascism or restore the glories of Greek Empire in the east.
  
• National Focus Tree for Turkey: Robbed of its empire in the last war, what future is there for Turkey in a new one? Continue or halt the reforms of Kemalism, stand as the protector of the Balkans in a new regional faction, restore the Sultan to the throne or found a new Islamic state.
  
• New Music Tracks
  
• New 3D Unit Models for Balkan and Turkish Armies
  
• Unique voiceovers for Bulgaria, Greece and Turkey