Hearts of Iron IV

Hearts of Iron IV

776 ratings
Expert AI 4.0
File Size
12.005 MB
Aug 11, 2016 @ 9:52am
Jul 13 @ 1:44pm
376 Change Notes ( view )

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Expert AI 4.0

Compatible with 1.5.*

Do you want to play vanilla HOI IV but can't find the challenge you need because the AI plays the game at a beginner level? This mod is for you. Nearly everything about the AI that is possible to mod has been overhauled (with over fifty thousand lines of script added) to create a more efficient AI.

That includes division designs, division production, equipment production, variants, research, diplomacy, construction, naval invasions, ideas and more. In other words how well the AI manages its country overall. There is absolutely massive room for improvement in these areas in the vanilla game. What is NOT fixed is how the AI moves its divisions, fleets and such except for tweaks here and there. This area is largely unmoddable.

Other than just making the AI more efficient, this mod also adds completely new AI features such as:
  • A scripted AI army focus system that allows any AI to choose from a wide range of different strategies and to logically prioritise research and variant design accordingly instead doing the same thing every game. There are over 400 template variations for the AI to design towards when creating divisions which gives it adaptability and adds replayability to the game.

  • New military coordination decisions for the player that allows you to influence what your allies do: launch coordinated naval invasions, change production priorities, check their stockpiles, coordinate lend-lease.

There is also a flexible in-game configuration tool (CTRL-SHIFT-O) that allows you to customise the difficulty and the AI in various ways at any point in the game:
  • Change certain AI behaviour or game balance.

  • Customise any country's build strategy (army, air, navy) from the specifics of template composition and width to land doctrine paths and fleet composition.

  • Add various different types of difficulty settings from simple bonus modifiers to scaling modifiers and even free division and equipment spawning until you find the challenge you need.

Some gameplay aspects have been slightly rebalanced to provide more interesting games (see here).

This mod works best with historical focuses. The overall progression of the game has been made more historical and the AI is more efficient with national focuses. Playing with all DLCs is highly recommended but not absolutely necessary.

Other mods:

-Expert AI: Expanded Technologies.
-Allied Construction Projects
-Strategic View Adjustments
Compatible mods.
Paradox forum thread.[forum.paradoxplaza.com]
Patch notes.
Suggestions & feedback.
Bug Reports.

Read before using:
  • If you are an experienced player and want a challenge especially as a major, you should still give the AI bonuses (see recommended settings here).

  • The AI takes certain shortcuts to be on a more level playing field with the player (listed in the 'details' thread). This mod is about having a competetive AI right now and not after a couple of major DLCs - these shortcuts allow the AI to do things that are simple for an experienced player to manage rather than give it an unfair advantage over the player.

  • This mod is meant to be played with historical focuses enabled but there should not be any game breaking issues that occur on non-historical. Historical focus setting in this mod does more than just changes the order in which the AI takes national focuses and which decisions it makes in events.

  • This mod is not balanced around playing with minor nations. If going on a conquest spree with minors is impossible or at least much harder, then it is working as intended.

  • 1939 start is not is not supported due to how much work it is to adapt to this mod.

  • Not achievement compatible.

  • It is recommended that you play with all DLCs but it is not absolutely necessary.

  • Multiplayer compatible when every player has this mod enabled.

  • This is a major overhaul that edits nearly every important file, therefore this is not compatible even with non-AI overhauls or mods that add or change technologies, advisors, new equipment etc. Compatible mods.


"Does this help performance by fixing AI division spam?"

The AI won't spam thousands of divisions in the late game, so yes. There is however a performance cost to all the additional AI scripting in this mod. In short, the game is a little slower from the beginning but lags out less during the late game.

"I picked Germany, set sliders to max and steamrolled all of Europe/world by 1939."

This is a sandbox game so you can play any way you like. However there are several problems with this: 1) Germany is by far the easiest nation, 2) the sliders only very marginally help the AI (so use more buffs through the EAI config), 3) there's a reason why many MP games use a massive list of house rules. The game is completely unbalanced without them and if human players can't deal with it then the AI sure as hell can't.

"Something ahistorical happened on historical mode."

It's not my intention to force the game to play out exactly historically whether it's Germany always losing by 45 or China not getting annexed by Japan. Customise the difficulty if you want to see some nation perform better.

"Can you make this compatible with my favourite mod X?"

It is unlikely that I will integrate other mods into Expert AI (or the other way around) for the time being. This mod is created around the vanilla Hearts of Iron 4 with painstaking effort to make an AI that understands how to play efficiently with the tools that it has.


Inspired by the 'AI Research and Division Tweaks' mod.

Thanks to everyone who have given feedback, made suggestions or reported problems.

Thanks to the following people for testing, contributions or specific ideas: Yossarian, VDNKh, RunsOnDiesel, Stjern, Scrublord, Zijistark, Axe99, Locomotive, Fabius.

Russian localization by santyrion. Ahistorical AI focus logic by mrkettyo.
Popular Discussions View All (21)
Jul 20 @ 3:42pm
Suggestions & Feedback
12 hours ago
PINNED: Bug reports
Jul 5 @ 10:22am
Struggling to even beat France?
< >
chrizeren Jul 20 @ 2:43pm 
does banning allies from front lines work properly? my allies keep death stacking units at my fronts, and making me take immense amounts of attrition. Otherwise, love the mod
Chris Jul 18 @ 4:53pm 
@Shadowziel It's a total conversion mod just like Kaiserreich. What do you think?
Pierre Retrowicz Jul 18 @ 1:29am 
Russian lang please
Shadowziel Jul 17 @ 2:30pm 
Is this mod compatiable with the Millenium Dawn Mod? (Sorry for spelling it wrong)
I checked the non compatiable mods and the ones that were and that did not tell me.
TheFilthyCasual Jul 17 @ 10:24am 
This might be outside your purview with this mod but this issue just cropped up.

I was having a really good game. Then the US shoved 50 divisions into my Italian beachhead, leaving it completely out of supply. Then all the countries that had troops in Spain decided to give them as expeditionary units to the Raj and completely anbandoned the front because the Raj sent them all to Burma; also I lost my entire army in Spain because it was now vastly outnumbered.

I want to be able to utilize my allies, but unless you're the Soviets or the Japanese, where you basically have no allies, your lack of control leads them to fucking a lot of shit up. What'd be great is if allies at war automatically offered the player command all their units as expeditionary forces, and continued to do so every time they made another division, so this kind of thing could be avoided.

You can do it now but it's tedious, because you have to tag <country> every time the AI makes another division.
Chondrite  [author] Jul 16 @ 1:53pm 
@Zohan Dwir - If you increased the difficulty with the sliders or the mod settings, then obviously it cheats. Otherwise no, it's just your lack of understanding the game and you should not be using this mod if you're not willing to improve.
Zohan Dwir Jul 16 @ 1:07pm 
The game becomes difficult with this, but I can't help but think that it's just a bunch of cheats for the AI and nothing more. Yeah, you made a ton of cheesy division templates that have nothing to do with historic ones and they do work well for the AI, yet overall this is turning the game into a fight of miserable detail hidden in the mechanics minutes. In 1941 France has more fighters than Germany, althouth it has maybe 40% of the industry. It also has a to of units and it's super-hard, but it's also super-stupid.:steamfacepalm:
派大星Po7 Jul 14 @ 11:37pm 
We need Chinese Translation
arado3 Jul 13 @ 6:40am 
@Chondrite thank you. I tweaked the difficulty levels and played without dynamic reinforcements and it's still a nice challenge. Is dynamic reinforcements tied to man power at all? That would be a good way to balance the feature.

Also, did your mod tweak the battleship spamming issues or has this been mitigated by 1.5.4? Probably a moot point with man the guns coming out but I'd thought i'd ask.

This mod breathes new life into the game, thanks again.
Chondrite  [author] Jul 13 @ 6:14am 
@arado3 It's kind of meant to do that. You'd probably want to use the other difficulty settings in a game like that. Cosmetic mods are fine if that's all they do.