Hearts of Iron 4 announced


Expert AI really makes for an interesting German-Soviet war. In most of my games as Germany, I’m building up for the big invasion and it ends up being anti-climactic. With the production improvements, some mild bonuses to the USSR and I guess Paradox operational AI improvements, it’s been a tough fight so far.

The mod increases the amount of time units take to receive reinforcements, reduces the amount of IC you get from occupation and greatly increases the effects of weather, particularly mud.

I’d rushed Panther tanks to have a fair number ready for 1941 and started off with a large successful naval invasion of Leningrad. I had better technology and better numbers in the air, and the advantage of radar. But the never-sufficiently-damned Soviet heavy tank divisions are so damned tough to penetrate and the infantry is so numerous.

I spent the summer and fall of 1941 making small-to-medium encirclements but I could never get the big break because there were always more Soviet reinforcements piling into the line. Due to fully-researched doctrine, the encircled Soviet troops are stubbornly resistant. Things get bogged down in Soviet counter-attacks, heavy fighting ruins the infrastructure and forces me to move my mobile forces to another section of the line. Overall I took about 4 million Soviet soldiers off the table before fall mud arrived, and another 2 million in the winter. But I haven’t conquered much territory, barely holding on to Minsk and western Ukraine and my forces in Leningrad are bottled up and constantly threatened.

The air war started out well. I largely skipped light fighters and used one of the German focuses to move ahead to 1944 Heavy Fighters. They are less agile but have so much firepower, range and hitpoints that exchanges were initially heavily in my favour. However, the newer Soviet fighters are much better and are trading much more evenly with my heavy fighters, and I have no where to go tech wise for the moment. Plus the Soviets make liberal use of anti-aircraft elements in their divisions, which makes my CAS losses very heavy.

I’m hoping that with the addition of heavily-modified Jagdpanthers and some mechanized elements my tank divisions will finally be able to penetrate the Soviet heavy tanks and have more momentum against the infantry in the 1942 campaign. If I can take a big enough bite out of the Red Army at once, then I can make more progress capturing territory. Though it’s still a long, long way to capitulation and years until I will be able to significantly improve my tank tech.

I’ve set it up so the Soviets get significant bonuses as they approach capitulation, so it will be a long struggle in the east. If the US gets a foothold or starts a strong air campaign it could get very bad.


Do they separate out the AI improvements with gameplay adjustments, in terms of separate mods? I spend a lot of my time playing minors and things like reducing captured IC can really limit your already limited capabilities. I’d like the AI improvements but I don’t want their balance adjustments along with it.


Not that I am aware of. I’m just running the main mod now. Maybe there is a version without the gameplay mods? There is a lot of configuration for the difficulty screen. It might be that you can turn off the IC limits.

Overall, you can still get 70% of the IC at harshest occupation law, so that part is not a huge difference from vanilla. I think right now I would like those extra factories though :)


I agree. My last two German game I tried Expert AI at Very Hard. Poland and Romania often end up in alliance and sometimes you can annex them without having to worry about partisans. That happened in one but not both games. First game I made decent progress capturing Lenigrad, close to Moscow, Kiev, Sevastapol, but not Stalingrad. I then got distracted by action in Africa and southern Russia next thing I knew my entire Northern Army was out of supply and the AI was pocketing and wiping it out.

Second game Russia declare war on me in the summer of 40, I was looking at attacking fall of 1940, so I was pretty well prepared. There initial attack fail other than near Prussia. I counterattacked but didn’t make much progress. It was clear that there was no way I was going to conquer Russia.

Next I tried Japan. Japanese focus tree is both interesting and frustrating, you pretty much are limited to picking one target, China, Russia, or Dutch East India. Japanese research is hobbled, but you can skip researching 1936 and 1940 fighter but going the Zero route and the skip building 1940 just carrier planes.
I ended going after China. It was interesting a challenging battle, I ended conquering it in 1940, I think largely because the first year+, I was strictly fighting Nationalist China, the Communist and the other warlord didn’t join the united front until much later. Unfortunately, German ended going to war in 1938 over Czech and by 1940 she was at war with everybody, tension was at 100% and she hadn’t even conquered the Czech and East Prussia had be over run by the Poles.

Finally, I tried America at Hard, and boosted Germany. This game Germany also went to war in late 38 over the Czech, but this time she managed to conquer them plus Romania and Poland. It actually might be a pretty interesting game to finish, but I finally burned out on the game for a while.

From my perspective the AI, while there is plenty of room for improvement is good enough. At higher difficulties, I can’t beat the AI just because of the sheer number of troops they field. (Quantity has a quality all it is own, as Stalin said.) Playing as allied country or Japan is risky because a challenging game really depends on German doing nearly as well as she did historically. Yet as we all know it was combo of good luck, bold gamble and weak response by the allies that allowed it to happen. Over the years, I’ve lost track of the number of times we’ve restarted board games like 3rd Reich, or World In Flames, because German failed to take out France by the end of 1940.

I’m looking forward to the next patch/update, but I’m a little fearful that addition of fuel will make an already challenging task for an AI Axis even more difficult.


As Mike says there are zillion option in Expert AI and you can change them during the game.
The AI improvements are primarily using better template, I believe somewhat making smarter focus choices/declaring war and a lot about making the AI use factories smarter.

The cheats (which primarily boost the AI not hurt the players) are highly configurable. Mostly the increase defense, manpower, production efficiency, and boost production for items the AI is short of. Finally, the big one is to reduce AI attrition, the AI isn’t good with dealing with supply, so you stick a lot of AI division on a mountain, send them into an areas without sufficient supply and all their equipment will break.

My favorite is the dynamic bonus which increase bonus the closer a country gets to capitulation, for a country like Poland it doesn’t mater much it takes too long for extra equipment and divisions to reach the front. But it is a big deal for China and Russia, and presumably Germany if you are play an allied country.


It’s really been an ongoing kind of silent improvement in the tactical AI. I noticed it a fair bit in my KR game as the Commune of France. I had some “volunteer” motorized-transitioning-armor divisions in the American civil war, and I was impressed by how quick it would respond to my movements, especially trying to get out of impending pockets. There are still situations where it does too much shuffling to cover the line (rather than attacking to close the gap) and the frontlines can still turn into a mess, but it’s much better than it was.

KR is interesting. I’d played a CoF game a while ago, and lost interest because it was build up, watch the socialists win in America, defeated Germany then ennui. This time I was just trying to farm some experience in the US civil war and the socialists were well on their way to victory before Canada invaded. I thought I had turned that around when I capitulated New England and destroyed most of the Canadian army in Ohio. But I forgot that Canada would also bring all of the Entente into the war. I capitulated the southern US faction but with troops from all the Entente countries the imbalance was too big and the CSA folded.

Probably I should have tried to declare war on the Entente so I could bring in more troops, but I didn’t realise how bad the situation was until it was too late. Now a year later I’m at war with the Entente anyway over freaking Sardinia and trying to think how I can bring back the socialists in the USA before New England can build too many factories. A war with Germany is probably going to happen pretty soon as well. Overall it seems pretty dire, which is a fun situation. Interesting how no two games of KR play the same.


KR has made playing small/medium sized countries so entertaining as well. I’ve really enjoyed playing a couple games as Egypt. I’ve started poking around in South America since they added so much content there this patch and it also looks to be interesting. Playing the remnants of France in Algeria is a lot of fun too.

While I know it’s a lot of work for the modders, Paradox’s post-release support model really combines well with mods. The base AI keeps getting better, there continue to be additional features and improvements that mods can leverage, and I know there are a lot of patch notes targeted specifically at limitations the mod community has raised.

Playing KR has been a terrific way to fill the time while I wait for Man the Guns.


Interesting thread on air combat resolution from a guy who decompiled the executable. I love that we can find out what the actual rules are here (and where they might fall short).



In the next update you will be able to tell convoys and fleets to avoid certain seazones. Strangely this doesn’t apply to naval invasion routing…



And on the forum someone asks the million dollar question about every “fix” they have to air and naval issues:

Will the AI be able to use the restricting seazone feature effectively?



When extremely abstract naval warfare with awkwardly not-abstract elements slams into highly detailed land warfare.




I was hoping it would be ammunition! Mines were important in the war, but I am starting to wonder about just how many things a user has to keep track of. Now we are researching and designing minelayers and minesweepers and thinking about which areas are mined. At least the devs are going to do something about the increasing number of techs and the non-increasing ability to get research done.

I played out my Commune of France game in KR until the point where I was capturing territory to get within range of America, but I kind of lost interest there. Started a game as the Union of Britain and it seems likely to remain interesting longer. Partly this is because the CoF decided to declare war on Germany the day after the Entente declared war on them. So just trying to keep mainland France from falling keeps me pretty busy so far (Spain and Portugal are in the Entente).

Britain does have landpower heft or as many factory slots as the CoF. I don’t really have a strong enough armoured force or the right geography to take out Germany in a lightning strike. I do have substantial resources but not enough to win the war against the rest of the world by myself. At least not quickly. I like picking a nation where the fight is going to stay interesting for a good while.


I think they jumped the Shark on this…what…on the release of HOI IV? I never play anymore. It’s just a chrome-addled 4X hiding in strategic WWII clothes at this point. If they would solve basic Air/Naval/Strategic Warfare issues instead of releasing new munchkin candy, I’d return, but all the promises of DLC “fixes” are just more “sugar rush” micro-detail…promises promises… I think I am done for good.

If I ever get the RTS WW2 itch again it’ll be Darkest Hour. I think Paradox has become for me the developer where I’ll be coming back for EU and Vicky titles…and that is it. And Stellaris every once in a while.


I have such a different take, @Navaronegun! I enjoy HOI4 more than the previous entries in the series and I enjoy it more now than at release. Guess it’s true you can’t please everyone. :)

It sounds like we can visually see and know what areas are mined, so I think it opens up some decisions without overwhelming with stuff to mentally keep track of. I find that once you have a lot of coastline, it can be a real pain in the ass to deal with the prospect of naval invasions pretty much everywhere. If I lack naval dominance but can successfully mine a few areas to wall off some invasion routes, I could see myself getting some real use out of this.

The naval game as it is right now is lacking in player interaction and decision making, in my opinion. You assemble a fleet, put them on a mission, then… that’s basically it. I think I’ll enjoy having some more choices of what ships to build and what to do with my navy beyond spamming the FOTM ship class. Well, potentially anyway, the devil’s always in the details.


I hear you. They made a conscious decision, IMO, to make a left turn at Albuquerque and go full 4X style, post HOI III. That’s OK, and it sells. But in this humble grognard’s opionion, any vestiges of it being a historical strategic wargame were left behind at that point.

Hey, I had fun playing my alternative universe bad guy South Africa who defeated the other bad guys in a later Third World War to become a major power. And where super-Battleships roam the earth and rule the seas. But after a while, I wanted to play a historical strategic wargame on World War II again. :)


Good point. I hadn’t thought about the potential to remove headaches.


I have to say that mines were not in my top 10 or even 20 things to add to the game. While mines were in important in WWII, I fear it is one more system that the human player can abuse in the pre-war period that AI won’t be able to deal with.


That’s one of the reasons why they only exist in war time, and go away soon after.
It’s probably not something that took a lot of effort and just fit the DLC.


One thing about the naval model that popped up in the current game. People tell you on the forum to build only Bbs since other stuff will tend to melt super quickly and the carrier bug makes using carriers tricky.

Except that I lost all my escorts in the apocalyptic naval battle and a few other actions. Suddenly my battleship fleet can’t actually find the enemy even in a zone as small as the channel. I figured with 90 percent of the world’s remaining battleships and a bazillion aircraft in the channel it would be safe to transfer an army across. I lost 24 divisions to a handful of enemy destroyers and my “grand fleet” never even showed up.