[EU4] An in-depth Guide to Fort Zone of Control Mechanics 

It´s like solving one of humanities greatest mysteries!

Good grief Paradox. It's not surprising people come to the conclusion that the system is broken or that the AI cheats when the way it works is absolutely nonsensical.

That sea return province looks so broken..

who at paradox thought of this system lol, when there's 20 stacks running around everywhere during war in the lategame its impossible to figure out where each one can go and cant go even with the ZoC mapmode. At least give us a mapmode which lets us click on the stack to show exactly where it can and cant go given its current return province or something. Or better yet make a less convoluted system that still has a decent level of complexity from which players can make decisions off but dont have to spend 5 minute studying the map everytime a few stacks arrive at a new front on your boarder or a fort gets taken somewhere

Now that I finally understand how forts really work, I am baffled at how Paradox could possibly create mechanics like this... Bypassing forts is simply unfair and gamebreaking in any situation.

Jesus this is way more complicated than I thought

Something I've found in my games that may explain why players think AI cheat on these rules is: if you path an army before forts are unmothballed and then the forts get maintained even if you wouldn't otherwise be able to move to the province where they're heading now that the forts are on because the game calculated the path before there were any zones of control your army will be able to move to its destination. This results in armies being able to skip forts that were not maintained before the start of the war so long as the pathing movement was calculated before the forts were maintained. I suspect that players who often keep their forts off and do not manually turn them on before the start of the war but rely on the checkbox to automatically raise forts and army maintenance when at war feature will see enemies 'cheating' when it comes to their forts because the enemy will have a day at the start of the war when all the forts haven't updated their zones of control because they were just turned on that day. This day gives the enemy's armies a chance to pathfind wherever they want in the player's land. The other side of this is you can get multiple of your enemy's forts if you declare war when they're mothballed and before you unpause direct an army to each fort in the enemy's land.

I've watched this video for the last 3 years and I still don't understand forts

Great video explaining a terribly presented mechanic! UI elements being obscure (return province) UI elements being incomplete (friendly+hostile ZoC overlaps) UI elements being completely absent (distance rule) Then there's the completely counter-intuitive & unrealistic results that the mechanics create. Oh yeah, and the loopholes relating to the transferring of units between multiple armies...... A terrible convoluted mess of a design.

This seems needlessly confusing and it makes me angry

Man I always thought that return provinces had something to do with retreating armies... Thanks for the thorough explanation!

Pls make more vids like this, you're so great

Please teach me more buddeh

Even after playing for hundreds of hours you can always learn something new in EU4.

Okay, thank you, you've made me understand the system more, which only made me even more sure that it's absolutely fucked. No army movement should work like this in any game ever. I can't understand why they couldn't come up with something other than this convoluted, unenjoyable bullshit.

Rule 1: You can go from any empty province to any other province Rule 2: A unit can always return to the last province it was in previously Rule 3: You can always move from a land province to an adjacent sea province regardless of any forts Rule 4 (Distance Rule): Units can move to any province that has a distance of 2 or less from the return province Rule 5 (Fort Rule): Units that are on a zone of control province can always move to an adjacent province Rule 6 (Friendly Zone of Control): You can always move to OR from provinces with friendly ZoC Rule 7: When your troops take a fort, the province reverts to whatever it would be if the fort was deleted (but it still generates a hostile ZoC against enemies)

I don't like the fort system. It's overly complicated. If I have to calculate graph traversals for something as basic as movement, the game design has failed. Also the UI in EUIV is too primitive to display the ZoCs properly, maybe PDX could look at XCOM or Civ for UI/UX a bit, not that Firaxis does a perfect job, but a lot of it is easier to grasp/use.

if this game keeps getting more complicated it is going to require a college course to understand Watched video and wow that is complicated as hell. Would you say it if more advantageous to build your forts one provience back or is it still effective to put them right in the boarder as they'll project a zone of control once you've started pushing the boarder back?

best eu4 youtuber hands down

If this isn't bad design - rules so complicated you can't grasp them and largely undocumented, and no UI element to show that 'province of origin' or anything else about it...

You are the unsung hero of eu4

arumba was wrong confirmed

My brain hurts

This is really helpful. One thing, though; the AI does *kind of* cheat. They can't access provinces that they shouldn't, however, if they can reach a province by any of these mentioned rules, no matter how far or how long it would take them, they can take the most direct path. This was apparently added to prevent exploits, however, it is easy to see that it could lead to them walking straight through a fort and thus people come to the opinion that it's broken.

"A bunch of enemy forts grouped together introduces no additional complications" except that you can occupy a fort inbetween others, but when you go back to where you came from its suddenly unreachable. Example: macedonia, edirne and constantinople are forts, start in tarnovo. move to plovdiv, occupy it, move to edirne, occupy it, move back to plovdiv. plovdiv still counts as zoc, edirne now also does. by the distance rule edirne is now unreachable. should it be retaken by its owner, you can suddenly move in.

Wow, the 2 province rule enlightened me. Now i understand why the ai can make moves that i could not fathom. Question: If the sea province is set as the return province, does the 2 province rule apply? Means you could move 2 spaces inland way from the water? Can you run THROUGH a fort with the 2 province rule ?

Reman your voice is butter for my cavities

Oh man this explains a lot, thank you sir!

First up, good video on explaining something I simply could not figure out at all by just playing the game. As an avid EU3 player I have just recently switched it up with EU4 and all the expansions (July 4th sale and all) this was one of those things as an EU3 player I had never encountered and was just baffled by. My intro game (playing England) and is playing around with the controls this was massively complicated and infuriating to the point I almost rage quit several times. I totally understand the desire to change things up, but man have they (Paradox) gone overboard with the changes, still learning, a little uneasy about how complicated the game has become. One of the reasons I never adopted Heart of Iron was the insane complication of the game mechanics making it very very hard to get into and to navigate around when your country/empire got too big, alas I am fearing a similar predicament, hoping some sort of automation comes along when I learn more taking away the need to pause every 30 seconds or so to just get a sense of what is actually happening.

Great videos man keep them coming. I am loving the quality and effort you put in. Considering setting up a Patreon as I am sure this takes up a lot of time and it would be nice to support someone condensing all of these wiki's. Keep it up!

The end of this video was like watching the god of knowledge download information directly into my brain. I finally understand movement mechanics after only a few hundred hours!

More really amazing and helpful information. Probably more actionable information per minute than I have ever seen before on a channel like this. Truly stupendous stuff!

Once again an excellent video. Great watching you - concise, informative, essential info. Great job.

Thank you! This was a huge help! Thanks for the great visuals, both from the custom gameplay and post-editing. You made it really easy to understand something I'd been struggling with. Love your videos!

Now you are officially my God .

That was actually much simpler than i thought it was. Thanks!

I have never paid attention to the return province, thanks for the great video clearing things up.

Rules: 1. 3:30 You can always move from an empty province to any other province 2. 3:41 You can always move to previous province; this won't exile your troops 3. 4:04 You can always move to a sea province 4. 4:18 You can move to any province up to *2 distance away* from return province 5. 6:28 You can always move into adjacent fort if in ZoC 6. 8:38 You can always move to/from friendly Zoc. The map can be misleading 7. 10:01 Occupied forts have no effect on yourself Rules 4, 5, 6, and notes e and f are the ones to remember. Try to not have 1 province thin ZoC walls Notes: a. 1:10 Types of provinces b. 1:40 Return province basics c. 2:54 or 5:26 Distance from return province extends into accessed countries d. 5:47 or 6:58 Rule 4 or 5 allows you to "ignore" forts on coasts if return province is the sea. Not sure how these are different e. 7:25 ZoC never crosses enemy borders, regardless of occupier f. 8:02 ZoC extends into neutral territory g. 9:30 Occupied forts do not have a friendly ZoC

This is the best EUIV vid I've ever seen. I learned more about this daunting game mechanic in a few minutes than in hours of playing and watching others complain about the 'broken' fort system.

Holy shit, Reman, ANOTHER video? You're on a roll!

Holy crap, this was frustrating me so much in a game the other day and I didn't even know this was a thing! Thank you Reman. Love your videos buddy.

Oh my god the sea rule! How did I miss that! And I thought I understood it well, great vid!

13:00 well since then they've admitted in the patch notes(1.24) that the AI ignored ZoC rules so you and wiz were wrong. Still a great video for understanding your own moments, but it didn't actually test AI movement enough. between patch 1.24 and this video I had a moment where I was mimicking an AI allys movements, we both had the return province in my territory, entered our enemys territory and started moving around, then after a while I couldn't follow him anymore because the fort blocked me but not my AI ally. In another game I saw the mamluks moving across a hostile fort and I saved and tag switched to see their return province which didn't seem to add up, tried mimicking their movement and suddenly it wasn't allowed anymore. Not sure if the AI cheats anymore, maybe they've truly fixed it.

Awesome Guide! Great work with with explaining it. I was getting kind of frustrated because I was playing Castile, and at war, England beached troops in Vizcaya, but was able to move between all the coastal provinces up there. Now I get why they could do that.

Man I saw few of your videos. Your videos are so good, informative and well made.. great job man. I played this game since it was published, and I learned from your videos... I am so amazed... keep the good work. sorry for my broken ENG

This video is amazing. It felt so mysterious before!

That trick of moving all your units to the "relief force" can save many games!

I like the mechanics. Thank you for the explanation. The last video about trade helped me a lot by playing as the Mayans and making a fortunes in Chesapeake Bay .

Fantastic video as always! Seeing a new Reman upload always makes my day. You've got a little background buzz on the audio though FYI, audible around the 4:11 mark.

AI can still walk through any damn province they want to 😥

Thanx for this video! I didnt even knew about this complex fort control system. Now I can use it in my benefit, instead of feeling frustrated about it.

Two videos in a week? Reman you'll spoil us!

One thing that I've learned to be cautious about is merging armies during a siege. I typically split my armies to avoid attrition, but when you merge them, the return province can get lost. I once got stuck on a single province I couldn't leave with an army too small to siege down the fort it was on, and couldn't disband it either.

I have been waiting for a video like this for a long time. It is really awful to see so much misinformation on fort ZoC, so many baseless accusations of the AI cheating and so forth. I am glad to finally have a link I can shut that down with.

Reman you know your stuff but for any one watching your video's they are watching to learn maybe slowing down your pace of talking on most of your video's would help many of times I have rewind it as you talk that quick. Still great knowledge and thanks for all your tips as well as HOI4.

Thank you, this guide is extremely helpful. I think I'll have to watch for these things ingame to really understand them but I get the basics now.

Thank you! I would guess that most people have the same problem I did: Not aware of the return province mechanic, that this is what really matters. I had no idea that the return province was the main thing the game used to calculate, so nothing made sense. I think I'm going to be using and abusing a lot of the things I've learned. For example, there might be more border gore between myself and an AI that I plan to attack in a later war, as I take provinces that can serve as amazing return provinces and let me access a ton of land with the forts the enemy has up.

Great video! The reason that people say that the ai cheats is because if they can get to a province in any way, they're allowed to take the shortest route to the province. This causes some problems, because the ai should sometimes only get to your province by taking the long route through Siberia, but they can just walk through your forts in India if that route exists. Edit: Clarity

I think the better way to do implement forts would be 1) blocking the movement between hostile forts or between hostile fort and the area with no access 2) high attrition/morale hit for passing through a province in the zone of control and slowed down movement through the zone of control, prevent reinforcements if a path to the friendly territory which is unrestricted by forts does not exist or is too long

Since the introduction of ''devastation mechanics'', having forts withing you territory and not just the border is very valuable. Devastation ticks down at 0.08 a month whereas you can get 10-15% devastation in one little war. It would take forever to tick down, but, provinces within the zone of control of a fort get an additional 0.80 down tick a month for a total of 0.88 a month. That is 11 times faster with a fort than without one. I have a fort in every state just for this reason alone. I can recover in 2 years from a war whereas without forts, you would need 20 years between wars to recover your 'devastation'... Anyways, great video :D

Reman you should unironically write a book with all the complicated mechanics.

OK, _this_ is confusing! But it's a lot better than the understanding I had previously. And at the very end of your video, I think maybe you've cleared up a puzzle for me. Thanks! I had a problem as Korea invading Ming. At one point, I took their fort and moved past it into open land (their land) that had no zones of control. But then I couldn't get out again. It was like a one-way door. I could roam around taking provinces that weren't within a zone of control, but I couldn't escape from them even through the province with the fort (which I still controlled). Eventually, I just made peace, so I could get my armies out of there. I controlled all of the provinces - the one I was moving from, the fort province, and the province I was trying to moving into. But if I understood you correctly, I reset the "return province" when I went into enemy land that no zone of control (because I'd taken the fort that had established that zone of control). That still seems screwy to me. But next time I play, I'll have to look for that "return province" icon. I never even knew it existed. So this video will help, even if I still don't understand everything. Thanks!

Everything in this game is quantum physics. Reman, you're a goddamn hero.

I believe, being able to only go the way you came was a previous itteration of forts, a large part of the confusiuon with forts is that they have worked diffierantly in past patches.

Great guide! Really nice job, achieving to make EU4 seem clear, and teaching stuff to 1000+ h players. Thanks a lot

Again great video!!! Man where are you? Give more EU4 content cheers!!!

Finally figured out what that fort with the flag means, thank you!

I don't know if this has been mentioned, but: If you issue movement orders ON THE DAY YOU(not when you get declared on)DECLARE A WAR, you can bybass forts entirely to go sit on whatever province you want. This is a very wonky bug and not 100% reliable, but I've used it to great affect, especially with Imperialism. *Yes, fully garrisoned forts. I repeat. Not mothballed forts.* It may have to do with a conditional access override bug, where you have conditional access that doesn't get canceled before you move your troops. Or it could just be some other type of bug. Or some other excuse(perhaps mechanics DO let this happen naturally and it makes sense code-wise but isn't intended. Or or or or. Point is, there ARE situations where you CAN ignore ZoC and just march wherever you want. Rare, unreliable, and I wouldn't bet my TTM run on it, but it happens.

Great video, didn't understand everything, but that rule of the return province will be so useful. I always play carefully anyway, and I try to not overlap ZoC with my forts to avoid problems. I think that's the simplest rule for building forts at least. If you don't overlap ZoC, you will see a more expected behavior.

Just thank the devs that there is a fort system, it used to take a long, long, long time to seige down a big country as it took a year or more for every single province. Yes, at the beginning of the game, you could do it with one troop, but that made them much more vulnerable.

I had a game as Spain with a fort in Navarra and France walked right through it. It was not mothballed and it was a level 4 fort. This was since the update that added the Pyrenees Mountains.

One thing needs to be mentioned here - AI completely ignores ZoC so dont for a second think that your troops (while retreating) can hide behind your own forts. They cant as the AI will simply stroll right through 3 overlapping forts projecting your ZoC and stack wipe you. I know this wasnt the case back when cossacks was released (patch 1.15 i think?) but now it is. Dont know when the ZoC was removed for AI but it must have been somewhere between 1.15 and 1.20. To expand on this: I was playing as Golden (now "Great") Horde in 1.15 and after a very long break - now. In 1.15 (since i rarely kept more than 1 fort around) ive had a single fort - my capital province + a fort on top of it (in Sarai as moving it away from the russian border was advantageous). This allowed me to lure enemy armies into that fort and easily stack wipe them as hordes get a bonus shock damage in plains (easy right?). If i got beaten by an enemy stack my troops retreated there into the safety of that fort. In 1.15 if i was pursued by an AI stack and the AI followed me into the capital fort - i just took a single "step" behind the fort opposite of where the enemy stack was coming from and that made the AI stack either sit there and try to siege the fort down or go around my capital forts ZoC if they wanted to reach my hurt stack (exactly as shown in the video). In 1.20 i followed the same rules and placed a fort on my capital of Sarai. I got into a war with Muscovy. Did some damage but got whooped and my units retreated to said fort and its ZoC. A Muscovite stack pursued so seeing this - i took one step to the opposite side of the incoming stack. You cant imagine my surprise when the enemy stack took a step into my capital province with a fort projecting a ZoC, movied past it in a straight line and wiped my stack. Since then i stopped keeping even a single fort anywhere as theres no point to them anymore. @Paradox. If youre making rules make them apply to both human players and AI. We know AI cheats in a ton of situations but forts and ZoC shouldnt be one of those instances.

This guy speaks enchantment table

I´ll bet this guy is a teacher. He´s great at this

Will you ever post more videos, Reman? You got me into EU4, and I've enjoyed every single thing you've put out.

Thank you very much for your guides. They are outstanding! Hopes you will keep making them :)

This looks like its meant to model supply trains. It would be handy if the graphics actually showed this, rather than just showing you the home province and making you calculate the distance yourself.

This video makes sense, but imo the fort system itself is convoluted and overly complicated. Thanks for clearing up the return province thing tho, I've never heard of it before today.

Great Video as always! The only thing I didn't know is that sea zone can be return province, because that situation almost never occurs naturally. It explains why Spain was able to bypass my forts when I played Mali, situation in which I assumed that AI was cheating :)

you're simply awesome, Reman

3:15 confuses me, why would olonets be a 2? wouldn't it be a 1 since its an neutral right next to the neutral 0?

Holy shit! It actualy makes sence. This has been so helpful

thx for that. this was giving me a headache for quite a while. Cheerz.

This cleared up SO MUCH. Thanks for the explanation!

Liked, Subbed, and I'm contemplating putting your video in my Sig for EU4 boards

Please try to throw some light into the combat system. I've spent several hours in debug mode, with ai off, just 1reg vs 1reg, trying to make sure the formulas are ok. And the information in the wiki seems to be wrong. The formulas work pretty well for casualties (rounding aside), but didn't work for morale.

Oh my god! I knew I recognized that song, I've been a longtime listener to iamsleepless (:

Watched this, institutions, and your trade ones. Very much like how you break it down (With edited help, like the arrows / #s), provide examples, and tips at the end. Only thing was at 5:35 ish, you where referring to reds land, but still in the fort mode. Hard to see where red was if you missed where Olonets was. Maybe add a little red arrow / box next time? Please make more. Some ideas off the top of my head: Navy / Naval combat. Army / Land combat. Exploration / colonies (Maybe added in with Naval / Army?) Leaders (Maybe added in with Naval / Army as well? Or at least respective ones) Diplomacy Culture / religion. (How to form X nation, maybe HRE etc)

"A unit can always return to the last province it was in previously" - This is not true if you split and/or merge armies while on a fort, you will get blocked by ZOC and be unable to liberate your own occupations from being under siege. This is especially annoying when there are 2 forts next to each other. That's the main thing I wish you covered in this video, how reorganizing armies while on a fort affects the mechanics. Also, understanding how the rules work doesn't make them any less arbitrary. With regards to people saying that you can't move between ZoC provinces, that's how forts were intended to work originally, but they change up the fort rules in pretty much every patch so it's hard to keep track of what is true when. I don't remember exactly when the return province mechanic was implemented (I want to say 1.16 but I'm not certain on that), but it was definitely long after forts were first added in 1.12. With regards to AI cheating, they absolutely do cheat: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-_OJrDvx8C-8.html (Arumba actually used the console in the next video to tag switch over to France and confirm that he would not be able to make the same move). It's possible that when Wiz wrote that post, it was true that the AI doesn't cheat, but that was over a year ago in patch 1.15. The most plausible explanation for this nonsense I've seen is that if the AI has any valid route to a province, it is allowed to ignore ZoC to get to that province, though I don't know if the devs have ever confirmed that.

Nicely done. Very useful information. Thank you.

Superb guide! Now I understand the mechanics assaulting large hostile territory is so fun! As long as you have the manpower ;)

guy in 2020 here .... I love you man!

thanks for teaching me what pedagogically means

What this video did for me is that before, the fort system makes me rage, now it’s just a sigh.

I love forts so much, they are tied with development as the best of the relatively recent additions to improve the game. Remember how useless they used to be? You would almost never build high level forts no matter how late in the game you were. Also, remember when you had to carpet siege *every* province! It took FOREVER to occupy France. Plus, you couldn't demand provinces you didn't occupy, which is almost absurd compared to the way things are now.

An excellent video, detailing an extremely dumb and over complicated system in a way that is actually understandable.

This is great - wish i could upvote it more than once. 1 Question though: With Strait crossings, do the sea tiles count torwards the distance rule or do the linked provinces count as adjacent?

I think Paradox should implement a new mission system for land battles, like with Mare Nostrum for the Navy. Siege enemy forts, hunt enemy units, defend own territory and forts.

Wow...i slogged my way through the wiki's page on this and somehow missed anything about the distance rule; lots of things make more sense now

Well when fort system came out it WAS that you couldn't move around zones of control. Maybe that's the source of the confusion.