I am Hearts of Iron IV, also known as HOI4, and am grand strategy computer wargame developed by Paradox Development Studio and published by Paradox Interactive. I was released worldwide on 6 June 2016. I am the sequel to 2009's Hearts of Iron III and the fourth main installment in the Hearts of Iron series. Like previous games in the series, I am a grand strategy wargame that focuses on World War II. The player may take control of any nation in the world in either 1936 or 1939.