Hearts of Iron IV

From Wikipedia, the free encyclopedia
Hearts of Iron IV
Developer(s)Paradox Development Studio
Publisher(s)Paradox Interactive
Director(s)Peter 'Arheo' Nicholson
  • Andreas Waldetoft
SeriesHearts of Iron
EngineClausewitz Engine
Platform(s)Microsoft Windows, macOS, Linux
  • WW: 6 June 2016
Genre(s)Grand strategy wargame
Mode(s)Single-player, multiplayer

Hearts of Iron IV, often abbreviated as HOI4, is a grand strategy computer wargame developed by Paradox Development Studio and published by Paradox Interactive. It was released worldwide on 6 June 2016.[1] It is 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, Hearts of Iron IV is a grand strategy wargame that focuses on World War II. The player can control any country in the world, starting either in 1936 or 1939. Players can choose to pursue the historically accurate sequence of events or not.

By May 2018, the game had sold a total of one million and a half copies worldwide.[2][3] As of June 2023, the game has sold over five million copies on Steam alone.[4] Since its release, Paradox has released numerous DLCs for Hearts of Iron IV, greatly expanding player choice.[5]


Hearts of Iron IV is a grand strategy wargame that primarily revolves around World War II. The player may play as any nation in the world in the 1936 or 1939 start dates in singleplayer or multiplayer, although the game is not designed to go beyond 1948. A nation's military is divided between naval forces, aerial forces, and ground forces. For the ground forces, the player may train, customize, and command divisions consisting of various types of infantry, tanks, and other units. These divisions require equipment and manpower to fight properly. The navy and air force also require men and equipment, including the actual warships and warplanes that are used in combat. Equipment is produced by military factories, while ships are built by dockyards. These military factories and dockyards are, in turn, constructed using civilian factories, which also construct a variety of other buildings, produce consumer goods for the civilian population, and oversee commerce with other nations. Most nations are initially forced to devote a significant number of their civilian factories to producing consumer goods, but as the nation becomes increasingly mobilized, more factories will be freed up for other purposes. Mobilization is represented as a "policy" that the player may adjust with the proper amount of political power, an abstract "resource" that is also used to appoint new ministers and change other facets of the nation's government. In addition to mobilization, there are other policies, including the nation's stance on conscription and commerce.[6]

Land in Hearts of Iron IV is divided into tiny regions known as provinces (also called tiles), which are grouped to form states. Each state has a certain amount of building slots, factory slots, and 5 infrastructure slots. The major seas and oceans (for warships) and the sky (for warplanes) are similarly divided into different regions. These provinces each have a type of terrain assigned to them that determines how well different types of units will perform in combat there. Divisions are placed in provinces and can attack enemy units in adjacent provinces. How well divisions perform in combat depends on various factors, such as the quality of their equipment, the weather, the type of terrain, the skill and traits of the general commanding the divisions, aerial combat in the region and the morale of both sides. Technologies can be researched to improve equipment. Military doctrines can be upgraded by using army XP, among other things, which often means that a more technologically advanced nation will have an edge in combat. If a division (or a group of divisions) successfully overwhelms an enemy province, they may occupy it. Some provinces may have victory points, which can push a nation closer towards capitulation if occupied. Occupying key provinces within a state allows the occupying power to access the enemy's factories and natural resources in that state. Resistance to occupation within a state can hamper the occupying power's control over it. Late in the game, nations may develop nuclear bombs if they have the proper technology, which can be used to devastate enemy provinces and states.[7]

Hearts of Iron IV also attempts to recreate the complex diplomatic relationships of the day. Nations may undertake a variety of diplomatic actions; they may sign non-aggression pacts, guarantee the independence of other nations, and offer or request military access, amongst other things. Another key feature of diplomacy is the ability to create a faction or invite other nations to an existing one. Factions represent the main alliances of the era, like the Axis and Allies (for gameplay purposes, real-world factions like the Axis and Allies are split into numerous smaller factions, like the Comintern, the Chinese United Front, and the Co-Prosperity Sphere). Faction members may assist each other in wars, making faction members precious assets. Some more clandestine diplomatic actions are also available. For example, the player may justify war against other nations, spread their ideology abroad, or stage a coup. Countries in the game may be democratic, fascist, communist, or non-aligned. Each of the four ideologies has advantages and disadvantages; for example, fascist nations can go to war with other countries easily, but other nations are not as willing to trade with them as they are with democratic countries. If a different ideology becomes too popular in a country, a referendum may be held that will peacefully convert the nation to the most popular ideology. Otherwise, ideologies may come to power violently through coups, civil wars, or forced subjugation by a foreign power.[8]

This diplomacy is further expanded through the addition of espionage in the expansion La Résistance, which extends gameplay in the management of occupied territories which is done differently according to player choices and ideology. Furthermore, the operation of spy networks allows nations to steal technology, gather information on an opponent's military, and engage in other espionage efforts.[9]

While Hearts of Iron IV does feature some scripted events, the game features a "national focus" system that makes fixed events less necessary than in previous installments in the series. Each country in the game has a "focus tree" with various "national focuses" that grant certain effects or trigger events. For example, for the Anschluss to occur, Germany must first complete the focus that is related to it. Other focuses can grant special bonuses, like faster research times for certain technologies or extra factories. While some bonuses (like extra factories) are very tangible, others (like improvements to morale) are more abstract. These abstract bonuses are represented by "national spirits" that can be temporary or permanent. Not all national spirits are granted by focuses, and not all spirits are entirely beneficial. Focuses are completed over time; only one focus may be worked on at once, and working on one consumes some political power. Initially, only a handful of key nations, like Nazi Germany, the United Kingdom, the Soviet Union, and the United States, had unique focus trees; all other nations shared a generic one. Subsequent updates and DLCs have added focus trees to other nations as well.[10]

Hearts of Iron IV also introduces the concept of "world tension", an abstract representation of how close the world is to global war, on a scale from 0 to 100. Aggressive actions by any nation can increase world tension, while peaceful actions can decrease it. Depending on the circumstances of a nation, like their ideology, a certain level of world tension may be necessary to perform certain actions, like justifying war against another country.[11]


Hearts of Iron IV was announced in 2014 and was originally slated for a late 2015 release.[12] At E3 2015, creative director Johan Andersson confirmed that the game would be pushed back from its original release window, with the new release date being scheduled for the first quarter of 2016. This was an attempt to resolve several issues encountered with the game.[13] In March 2016, it was announced that the game, built with the Clausewitz Engine, would be released on 6 June 2016, which was the 72nd anniversary of the Normandy landings.[1]

Downloadable content[edit]

DLC timeline
2016Together for Victory
2017Death or Dishonor
2018Waking the Tiger
2019Man the Guns
2020La Résistance
Battle for the Bosporus
2021No Step Back
2022By Blood Alone
2023Arms Against Tyranny
Name Accompanying Patch Type Release Date Description
Together for Victory[14] 1.3


Country Pack 15 December 2016 Together for Victory is a country pack that adds content to multiple nations within the British Empire: Canada, Australia, New Zealand, South Africa, and the British Raj. It also expands the gameplay mechanics between puppet states and their masters, with a special autonomy system that determines a subject nation's degree of independence. Features like an expanded Lend-Lease system and the sharing of technology are also added.[15]
Death or Dishonor[16] 1.4


Country Pack 14 June 2017 Death or Dishonor is a country pack that adds content to several minor powers in Central Europe and the Balkans, which include Yugoslavia, Romania, Czechoslovakia, and Hungary, while also featuring the ability to license military equipment to other countries.[17] If Together for Victory is not owned, the expansion also adds limited puppet levels to the game. Following the release of the 1.10 "Collie" patch, content for Yugoslavia and Romania was reworked.[18]
Waking the Tiger[19] 1.5


Expansion 8 March 2018 Waking the Tiger is an expansion that fleshes out the Second Sino-Japanese War with new content for Japanese-controlled Manchukuo, as well as Nationalist and Communist China, and a shared focus tree for the Chinese warlords of Guangxi, Yunnan, Ma, Shanxi, and Sinkiang. The expansion also adds new opportunities for alternate history within the focus trees of Germany and Japan, which were expanded, and several new formable nations were added. In addition, special projects and policies can be enacted with unique decisions, and several changes to the management of generals are present in the expansion.[20]
Man the Guns[21] 1.6


Expansion 28 February 2019 Man the Guns is an expansion that improves the naval combat aspect of the game with the inclusion of a ship designer, although numerous other changes and new features are also present in the expansion, such as adding content for the Netherlands and Mexico and also including new alternate history paths for the United States and the United Kingdom. The expansion also adds fuel as a resource separate from oil, and government-in-exile mechanics.[22]
La Résistance[9] 1.9


Expansion 25 February 2020 La Résistance is an expansion that adds espionage and occupation mechanics. Intelligence is greatly expanded, while occupation and resistance are completely reworked. The expansion also includes a revamped focus tree for France (both Free and Vichy), a new one for Portugal, and two focus trees for the different sides of the Spanish Civil War, one for the Nationalists and one for the Republicans. It also allows the civil war to spiral into a much bigger conflict.[9]
Battle for the Bosporus[23] 1.10[a]


Country Pack 15 October 2020 Battle for the Bosporus is a country pack that adds new unique focus trees for the Balkan countries such as Greece,[25] Bulgaria,[26] and Turkey.[27]
No Step Back[28] 1.11


Expansion 23 November 2021[29] No Step Back is an expansion that adds railroads, armored trains, railway guns, and a tank designer, with the possibility of customising chassis, weapons, and engines. It also introduces the general staff and adds unique focus trees the Baltic countries, and a reworked one for the Soviet Union. An additional free update reworks the Polish focus tree.[28]
By Blood Alone[30] 1.12


Expansion 27 September 2022 By Blood Alone is an expansion that adds new peace conference options, a plane designer, unit medals, and embargo interaction. It also includes a reworked national focus tree for Italy, as well as new national focus trees for both Switzerland and Ethiopia.[31]
Arms Against Tyranny[32] 1.13

"Stella Polaris"

Expansion 10 October 2023 Arms Against Tyranny is an expansion that adds unique focus trees for the Nordic countries, military industrial organizations, and an international market feature.


Hearts of Iron IV was developed to be more open-ended than previous games in the series. Partially as a result of this, the game can be more readily modded than its predecessors.[33] According to game director Dan Lind, 64% of Hearts of Iron IV players use mods.[34] Many mods do not change the gameplay experience drastically, and as such have become mainstays of the community, for example, 'Player-Led Peace Conferences', which gives the player more control over the outcome of the game. Also, several total conversion mods that dramatically change the game have been developed and released in many places, like the Steam Workshop. Some mods have been successful enough to attract attention from the media, including the following, amongst others:

  • Kaiserreich: Legacy of the Weltkrieg, a mod set in a world where the Central Powers won World War I. Kaiserreich is considered the largest and most in-depth Hearts of Iron IV mod by many community members.[35][36]
  • Old World Blues is a mod set in the Fallout universe. This mod has been praised for its effective portrayal of the Fallout series within a grand strategy setting.[37][38]
  • The New Order: Last Days of Europe (TNO), is a mod set in a world where the Axis Powers won World War II.[39] The mod has received praise for its rich storytelling and the dark and esoteric atmosphere that is present within the mod.[39]

Some other mods have also attracted controversy for racist and fascist overtones, such as Deus Vult, a mod that adds the Knights Templar to the game and allows the player to commit various atrocities.[40]


Hearts of Iron IV was a commercial success.[2] It sold more than 200,000 units within two weeks of its launch, which made it the fastest-selling historically-themed Paradox title by that time, ahead of Crusader Kings II and Europa Universalis IV.[45] The game's sales surpassed 500,000 units in February 2017,[46] and 1 million units in May 2018. It was the first Hearts of Iron game to reach the million mark, and the third Paradox title after, Crusader Kings II and Europa Universalis IV to do so.[2] The game received "generally favorable reviews" from critics, according to the review aggregator Metacritic.[41]

GameSpot gave the game a positive review, writing that "Hearts of Iron IV embodies the hard truths about all-consuming war and the international politics that guide it." It argued that the tutorial was the only weak point, and that "for the dedicated, Hearts of Iron IV could end up being the best grand strategy game in some time."[42]

It was also reviewed in Kotaku, with the reviewer writing it was "overwhelming in both its depth and, more importantly, its complexity" and arguing that some players unfamiliar with the franchise might find the game interface too complex to navigate easily.[47]

IGN wrote a positive review, describing it as "an incredibly complex World War II simulation that will require potentially hundreds of hours to master, both in-game and poring over wiki articles that read like an economics textbook", but adding that "the payoff is brilliant for those willing to put in the time to learn". The review praised the layout, writing "thanks to an unusually striking look and clean, easily navigable interface, the biggest challenges Hearts of Iron 4 presents us with are the good kind: strategic planning, division composition, and fine-tuning economic and political policies". IGN went on to conclude that Hearts of Iron IV "is a strong contender for the title of the ultimate armchair-general game. The biggest problems I can point to are almost all performance-related, putting a slow, frustrating finale on what is otherwise an ingeniously detailed strategic stimulation of just about every aspect of 20th-century global warfare".[43]

A review in PC Gamer described it as a "unique, beautiful, thrilling wargame", specifically praising its frontline system and production mechanics, but also criticising the ideology system for being too bland, and finding that combat was somewhat unintuitive, writing "while I found several flaws when I stood close to the tapestry, it's important to remember that Hearts of Iron 4 exists to encompass the whole sweep of the war".[44]

Polygon praised the openness of the game, writing that "Hearts of Iron 4 goes a step further, allowing players to take control of nearly every single nation-state in the world during the same period. If you want to play as Eleazar López Contreras, a Venezuelan fascist with two army divisions and 12 fighter planes to his name, you can give it a go".[48]

In 2022, six years after the game's release and shortly after the By Blood Alone expansion, Hearts of Iron IV hit a concurrent player record of about 70,000,[49] owing to a week-long deal that temporarily made the game free-to-play. The year prior, the game had reached a record of 68,000.[50]

See also[edit]


  1. ^ The Patch 1.10, aka "Collie", was released only to beta testers. It was superseded by patch 1.10.1 which coincided with the release of Battle for the Bosporus[24]


  1. ^ a b Dingman, Hayden (Mar 15, 2016). "Paradox Interactive reveals release dates for Hearts of Iron IV and Stellaris". PC World. Archived from the original on September 12, 2016. Retrieved September 9, 2016.
  2. ^ a b c Valentine, Rebekah (May 21, 2018). "Hearts of Iron IV sells one million copies". GamesIndustry.biz. Archived from the original on August 23, 2018.
  3. ^ "Hearts of Iron 4 sells a million copies, gets a special edition". PCGamesN. Archived from the original on 2021-12-11. Retrieved 2021-12-11.
  4. ^ "Hearts of Iron IV -". SteamSpy - All the data about Steam games. Archived from the original on 2023-06-26. Retrieved 2023-06-26.
  5. ^ "Next Hearts of Iron 4 DLC beefs up Scandinavia, Winter War". Wargamer. 2023-06-07. Retrieved 2023-07-11.
  6. ^ Apolon (June 29, 2016). "'Hearts Of Iron 4' Beginner's Guide: Tips, Tricks and Strategies For Mastering The Basics". Player.One. Archived from the original on February 21, 2019. Retrieved January 8, 2019.
  7. ^ JAFalcon (March 18, 2016). "Hearts of Iron IV developer diary talks about nuclear weapons". GameWatcher. Archived from the original on February 21, 2019. Retrieved February 20, 2019.
  8. ^ Hannley, Sean (June 7, 2016). "Review: Hearts of Iron IV". Hardcore Gamer. Archived from the original on February 21, 2019. Retrieved February 20, 2019.
  9. ^ a b c Hafer, T.J. (October 19, 2019). "Hearts of Iron IV: La Resistance announced, adds spies and commandos". PC Gamer. Archived from the original on 2019-10-19. Retrieved 2019-10-19.
  10. ^ Dumitrescu, Andrei (October 4, 2015). "Hearts of Iron IV Details Italy, National Focuses and Initial Setup". Softpedia. Archived from the original on February 21, 2019. Retrieved February 20, 2019.
  11. ^ Priest, Simon (May 8, 2015). "World Tension and neutrality in new Hearts of Iron IV dev diary". GameWatcher. Archived from the original on February 21, 2019. Retrieved February 20, 2019.
  12. ^ Frank, Allegra (March 15, 2016). "Hearts of Iron 4 launches this 'D-Day'". Polygon. Archived from the original on March 16, 2016. Retrieved February 12, 2019.
  13. ^ Hafer, Todd (13 June 2015). "Kicking Hitler Repeatedly in the Kidneys in Hearts of Iron 4". IGN. Archived from the original on 15 March 2018. Retrieved 19 June 2015.
  14. ^ Parrish, Peter (November 1, 2016). "Hearts of Iron IV: Together for Victory DLC to expand Commonwealth". PC Invasion. Archived from the original on November 3, 2016. Retrieved July 31, 2020.
  15. ^ Brown, Fraser (December 16, 2016). "Hearts of Iron IV: Together for Victory review". Rock, Paper, Shotgun. Archived from the original on March 1, 2019. Retrieved February 27, 2019.
  16. ^ O'Connor, Alice (April 26, 2017). "Hearts of Iron 4: Death or Dishonor announced". Rock, Paper, Shotgun. Archived from the original on December 4, 2020. Retrieved July 31, 2020.
  17. ^ Cobb, James (June 14, 2017). "Review: Hearts of Iron IV: Death or Dishonor". Wargamer. Archived from the original on November 12, 2020. Retrieved February 27, 2019.
  18. ^ "HOI4 Dev Diary - Yugoslavia and Romania". Paradox Interactive Forums. Archived from the original on 2021-01-23. Retrieved 2021-01-22.
  19. ^ O'Connor, Alice (November 16, 2017). "Hearts of Iron IV prods China in Waking The Tiger". Rock Paper Shotgun. Archived from the original on October 24, 2020. Retrieved July 31, 2020.
  20. ^ Robinson, Joe (March 19, 2018). "Review: Hearts of Iron 4: Waking the Tiger". Wargamer. Archived from the original on November 9, 2020. Retrieved February 27, 2019.
  21. ^ Donnelly, Joe (May 19, 2018). "Hearts of Iron 4: Man the Guns expansion grows its naval game". PC Gamer. Archived from the original on August 7, 2020. Retrieved July 31, 2020.
  22. ^ Donnelly, Joe (May 19, 2018). "Hearts of Iron 4: Man the Guns expansion grows its naval game". PC Gamer. Archived from the original on March 8, 2021. Retrieved February 27, 2019.
  23. ^ "For centuries, the Bosporus and Dardanelles have been key to strategy in the Mediterranean. How will they act when war comes to their doorstep? Shape their destiny in Hearts of Iron IV: Battle for the Bosporus, releasing 15th October 2020". Twitter. Archived from the original on 2020-09-23. Retrieved 2020-09-23.
  24. ^ "Patch 1.10.1 Collie Live - Checksum dd56 (Not for problem reports)". Archived from the original on 2021-06-03. Retrieved 2021-06-03.
  25. ^ "HOI4 Dev Diary - Greece". Paradox Interactive Forums. Archived from the original on 2020-09-10. Retrieved 2020-09-09.
  26. ^ "HOI4 Dev Diary - Bulgaria". Paradox Interactive Forums. Archived from the original on 2020-09-29. Retrieved 2020-09-16.
  27. ^ "HoI4 Dev Diary - Turkey". Paradox Interactive Forums. Archived from the original on 2020-09-27. Retrieved 2020-09-23.
  28. ^ a b "Hearts of Iron 4 'No Step Back' DLC trailer reveals Soviet theme". Wargamer. Archived from the original on 2021-06-03. Retrieved 2021-05-21.
  29. ^ Hearts of Iron [@HOI_Game] (October 21, 2021). "From the womb of Mother Russia, Machines are born - But it is in the blood of the People the Union survives! Hearts of Iron IV: No Step Back will release November 23rd, 2021" (Tweet). Retrieved 2022-08-02 – via Twitter.
  30. ^ Hearts of Iron IV: By Blood Alone - Official Announce Trailer, archived from the original on 2022-06-08, retrieved 2022-06-08
  31. ^ "Expansion - Hearts of Iron IV: By Blood Alone on Steam". store.steampowered.com. Archived from the original on 2022-06-07. Retrieved 2022-06-08.
  32. ^ "Expansion - Hearts of Iron IV: Arms Against Tyranny on Steam". store.steampowered.com. Archived from the original on 2023-06-07. Retrieved 2023-06-07.
  33. ^ Haas, Pete (23 January 2014). "Hearts Of Iron 4 Coming In Early 2015". Cinema Blend. Archived from the original on 24 January 2014. Retrieved 29 April 2019.
  34. ^ "Almost two thirds of Hearts of Iron 4 players use mods". PCGamesN. Archived from the original on 2019-10-28. Retrieved 2021-06-02.
  35. ^ Borsilli, Timothy (May 19, 2020). "Why Kaiserreich is (Still) the Ultimate Hearts of Iron 4 Mod". Wargamer. Archived from the original on July 30, 2020. Retrieved June 1, 2020.
  36. ^ Plunkett, Luke (October 3, 2020). "Kaiserreich, The Mod That Changes The World". Kotaku. Archived from the original on April 22, 2021. Retrieved August 25, 2020.
  37. ^ Ryan, Denis (May 18, 2018). "Old World Blues translates Fallout to grand strategy". Rock, Paper, Shotgun. Archived from the original on July 12, 2020. Retrieved July 12, 2020.
  38. ^ Klepek, Patrick (February 27, 2018). "Ambitious 'Hearts of Iron IV' Mod Transforms WWII into the Fallout Universe". Vice. Archived from the original on June 30, 2020. Retrieved August 25, 2020.
  39. ^ a b Borsilli, Timothy (August 17, 2020). "The New Order Is a More Narrative Driven Hearts of Iron 4 Mod Experience That's Both Compelling and Bleak". Wargamer. Archived from the original on August 18, 2020. Retrieved August 17, 2020.
  40. ^ Winkie, Luke (June 6, 2018). "The Struggle Over Gamers Who Use Mods To Create Racist Alternate Histories". Kotaku. Archived from the original on February 28, 2019. Retrieved February 27, 2019.
  41. ^ a b "Hearts of Iron IV PC". Metacritic. Archived from the original on May 29, 2015. Retrieved September 9, 2016.
  42. ^ a b Starkey, Daniel (2016-06-08). "Hearts of Iron 4 Review". GameSpot. Archived from the original on 2016-06-11. Retrieved 2019-02-24.
  43. ^ a b Hafer, T.J. (June 6, 2016). "Hearts of Iron IV review". IGN. Imagine Games Network. Archived from the original on June 6, 2016. Retrieved September 9, 2016.
  44. ^ a b Zacny, Rob (June 9, 2016). "Hearts of Iron 4 Review". PC Gamer. Archived from the original on June 9, 2016. Retrieved September 9, 2016.
  45. ^ Francis, Bryant (June 21, 2016). "Hearts of Iron IV becomes Paradox's fastest-selling historical game". Gamasutra. Archived from the original on October 25, 2020.
  46. ^ Grubb, Jeff (February 20, 2017). "Paradox sells over 500,000 copies of WWII grand strategy game Hearts of Iron IV". VentureBeat. Archived from the original on August 3, 2018.
  47. ^ Plunkett, Luke (June 6, 2016). "Hearts Of Iron IV". Kotaku. Archived from the original on June 8, 2016. Retrieved September 9, 2016.
  48. ^ Hall, Charlie (July 19, 2016). "Hearts of Iron 4 review". Polygon. Archived from the original on 2016-07-20. Retrieved 2019-09-07.
  49. ^ Allsop, Ken. "Hearts of Iron 4 DLC drives grand strategy game to record player count". PCGamesN. Archived from the original on 2022-10-01. Retrieved 2022-10-26.
  50. ^ Robinson, Joe. "Hearts of Iron 4 hits new concurrent player record five years after launch". PCGamesN. Archived from the original on 2021-12-16. Retrieved 2021-12-16.

External links[edit]