Difficulty level in my opinion:
Easy: Hearts of Iron 4
Medium: Crusader Kings 3
Hard: Europa Universalis 4
So if you can play CK3 & EU4 then you should have no troubles learning HOI4.
Hearts of Iron 4 is 80-90% war. There is some diplomacy there too. But that's not the focus of the game. It's mainly about fights.
Also, since you want to learn, allow me to teach you a few things. You'll have no idea what I'm talking about, but after you get the basics of the game you can come back here and switch from basic to advanced in no time:
1. Divisions:
- Each type of terrain has a fixed combat width which determines how many divisions can enter combat in a provice, so there's no 1 division template fits all.
Urban 96
Plains/Desert 90
Forest/Jungle 84
Hills 80
Marsh 78
Mountains 75 (Mountaineers with 25width are ideal)
- The elite/reserve designation are very useful in order of getting equipment.
- The important stats
HP life of the soldiers
ORG how much they remain in battle before they retreat (40-50 org is good; only infantry, motorized and cavalry increase it)
SUPP how much supplies it uses (if you have issues with that give them logistics company)
SOFT ATK vs HARD ATK on the bar below it shows the % soft atk to hard atk ratio of the division; hard attack only damages divisions with hardness so no infantry; so soft attack good vs infantry; hard attack good vs armor.
DEF / BREAK / ARMOR / PIERCE, DEF AND BREAK are opposed, ARMOR and PIERCE are opposed. So if you attack with high pierce a division with low armor you're going to do a lot of damage on their armored units. While DEF vs BREAK does the same but for non-armored units.
ENTRENCHMENT combat bonus on defense
- In general you need attack, defense, garrison and ports defense divisions:
ATK divisons need good stats and breakthrough/pierce so they can push through enemy lines.
Good divison templates: (you will check this one a lot)
STANDARD INFANTRY (hold the line & attack only when in advantage): 11 infantry + 1 anti-air support. (fits well into forest, hills and plains with minimal penalties)
*as a rule of thumb, having fully supplied troops is more important than having perfect combat width.
STANDARD ATK: 11 infantry + 4 artillery: anti-air, artillery, entrenchment, radio, logistics. (30 width)
STANDARD PORT DEFENSE: 10 infantry and sometimes: entrenchment, anti-air, artillery
STANDARD GARISON: 10 cavalry + military police. (increase it to the max if you can because the more cav in the divsion the less equipment is used per suppression)
STANDARD TANKS: 10 tanks + 10 motorized + 2 anti-air (42 width): anti-air, artillery, entrenchment, engineer, logistics. (just like infantry except enginner swaps radio)
STANDARD MOUNTAINEERS: 8 mountaineers + 3 artillery (25 width): anti-air, artillery, entrenchment, logistics (no radio)
STANDARD MARINES: 9 marines + 4 artillery (30 width): anti-air, artillery, entrenchment, logistics (no radio; entrenchment is most important here gives bonus to amphi)
TRASH PARATROOPERS: 3 paratroopers
STANDARD PARATROOPERS: 10 paratroopers: support artillery
- In your officer corps assign yourself early game when you got the command power and political power a low level general, because it gives you daily military XP.
- Get divisions to train early on, don't shift+click on them just click so they train even when they are level 3 so they give you daily military XP as well.
2. Army Doctrines:
- Doctrines are the main way to improve the effectiveness of your troops. (troops stats upgrade if you will; equipment and generals also help, but this is the main thing)
Mobile Warfare for tanks. Particullary the right paths for Blitzkreig and Mobile Kreig are more valueable because it gives you a lot of tank bonuses and that's more valueable than boosting your mobile infantry on the left (and the recuritable population, which you can get through upgrading your conscription laws).
- Superior Firepower is the most beginner-friendly doctrine as it gives you bonuses to your infantry (I know what I'll pick lol) especially if you add artilley, which most new players do. Integrated support on the right gives you +50 soft attack which is massive, for the next choice if you stick to infantry go right Shock & Awe, if you're using tanks too get left Airland Battle.
- Grand Battleplan is perfect for defense. It gives you high entrenchment, especially the first option gives you +10 entrenchment which is just huge, especially as: UK, USSR and China. The right path Inflitration reduces your supply lines and gives you 25% bonus to fighting at night which is 1/3rd of the battle
- Mass Assault is great for reducing supplies and having as many divisions as possible. The right path on Mass Mobilization gives you reduces your combat width by 0.4 meaning you can put more battalions and more stats into the same units and gives you +5.00% manpower so is good for countries with low manpower, good vs AI but not that good in multiplayer as your army will be significantly weaker. The left side Deep Battle is better as in more competitive because it gives you -20% supply usage which is huge, allows you to put more divisions on the frontline overall, and you still get that 0.4 combat width reduction so not only you can fit more divisions for the same amount of supply but also are getting stronger divisions. (basically: left - supplies; right - manpower; so if you play like USSR you have no reason to take the right)
3. Navy Doctrines:
- If you want lots of Battleships and Cruisers then Fleet in Being.
- If you only go for submarines then Trade Interdiction.
- If you're doing lots of Carriers and focus on them then Base Strike.
Each doctrine provies bonuses for each type of ships but again is specialized. (anything that boosts your fleet's organization and armor is important)
4. Air Doctrines: (agility is very important here, makes your planes harder to hit, keeping them alive longer)
- Strategic Destruction for Bombers. Gives you huge bonuses to strap bombing, and fighters 10% boost to agility, although battlefield support is overall better for cas.
- Battlefield Support for CAS. The right path is better as it gives you more chance for flying aces. Also gives you some bonus to naval attack.
- Opperational Integrity for Tactical Bombers. Gives less bonus to ground attack than battlefield support but gives the same naval attack. Increase attack bombers strap bombing and defense, and you also get 10% fighter boost like in strategic destruction.
- To unlock them you need Army/Navy/Air XP that you get through military combat, focuses or military branch chiefes. For some command power and political power you can assign army, navy and air commander. They will give you a bonus to that branch as well as daily military/navy/air XP.
- These army/navy/air commanders differ from your high command as they also give you that military XP not just the bonuses. Having that XP coming in is important.
- Some good battlefield opperations are: Forced Attack & Last Stand.
- Command power is limited, so it's always worth saving up for a Genius or Expert if you can. (but you don't need armor expect if you're not going to go tanks)
- Army logistics is very good, infantry officer is also very good, night opperations for air is very good.
- A theorist also helps you to save a lot of army XP.
- When you organize your navy, if you merge all your ships together in one port and press the Balance button, it will split them up into task forces that are not only balanced but also have the right number of screening efficiency. It's even going to assign relevant icons by itself.
5. Production:
- The economy law is one of the best laws you can take in the game, war economy is the best and get it ASAP.
- If you find that you lose a lot of civillian buildings because you need to trade for resources you already have, try reducing your trade laws.
- Build first in region with high infrastructure because that will affect how quickly a building is constructed.
- If you increase the infrastructure in a state with resources, you also increase the amount of resources that you get.
- Anti-Air building doesn't target enemy fighters, only enemy bombers or CAS when they are completing a mission in that region.
- Radar is super useful for targeting enemy aircraft and ships as well as enemy units in nearby regions.
- Rockets are crap so don't worry about that.
- Nuclear reactors are really fun but a late-game tech.
- You want to build only civilian factories until 1938 or very early 1939, then you can swap over to military factories but you want to make sure you build civs.
- Getting rid of Consumer Goods is very important so if you have a focus that gets you rid of that do it.
- War Bonds decisions once you are at war will also help you a lot.
6. Research:
- A penalty of under half a year or so is fine for most techs.
- Pick Concentrated Industry if you're confident you won't get bombed or Dispersed Industry if you think you will get bombed.
- The Fuel Refining tech also increase the fuel per oil you get from the ground and oil that you trade not only from the oil factories you build. They're important.
- The late game techs of nuclear and rocketry are only worth as a major nation and not ahead of time as they take quite a lot of time to complete.
- On Weapons & Equipment top line increases their defense and bottom line increases their attack.
- In the special troops the top provies better stats and increases their effectiveness, the bottom allows you to build far more special divisions overall, bottom is better.
- Trucks and Trains are very important to provide supply to your troops. Research early in the game and put a bit of military factories on each.
- The most important techs to start with are the: Electronic Enginnering/Mechanical Computing, and in industry the Production, Construction ones.
- Then go in the synethic technologies if you need them, like if you play Italy or Germany.
- Then move over to either Aircraft or Artillery technology.
- After this point look for infantry technology. After that any special forces that you need, as well as any tank classes that you plan on building.
- All while keeping on top your industry and your electornics to the max.
- Radio is pretty important and also quick to reserach, so if you're waiting for the year to pass by to reserach something new research a radio until then.
- If you have a research that provies an airtime bonus, start research the previous technology before completing the focus, this way the reduction'll add to the next one.
7. Supplies:
- Each divison has a supply usage depending on its combat width and composition.
- Supplies are delivered to your divisons automatically through Supply Hubs which are connected to your capital by railways. You can see it more clearly with F4.
- The lighter the blue is the more supplies available in a certain province. The darker the blue or the region is yellow or orange then the less supplies is.
- When you add divisions in a province they may consume supplies to the provinces becomes a darker blue or yellow or orange.
- Red or yellow provinces means that those divisions are lacking supplies.
- Based on that they are going to take attriction, so they are going to suffer losses daily sitting there.
- If they are on a blue provice they are fine, if they are in a yellow province they are slightly unsupplied it's not too bad, if it's on a red provice it's bad they take attrition.
- You can also check supplies when you're in the normal F1 mode by seeing whether there's a yellow, orange or red box next to the troops.
- Generally, you want to make sure your divisions have full supplies otherwise they are going to take those attrition damages.
- They also suffer a reduction of their stats in combat including attack, defense and organization.
- How to fix supply? it can come from having too many divisions in a single province so just move them.
- Another way is by building Supply Hubs near the frontline. The more supply hubs you have, the more supplies there will be.
- The problem is supply hubs are expensive, they cost about twice as much as a civilian factory.
- If you do decide to build them, you just need to make sure they are connected by a railway line to your capital.
- You can also increase your naval base to increase your supplies.
- Another thing you can do is increase supplies going to your existing hubs: by upgrading the railways.
- You can upgrade them up to level 5 to increase supplies. This has to be consistent though. If one part of your railway to the capital is level 1 all is level 1.
- You can upgrade the railway by clicking on a supply hub and selecting the upgrade railways button. Or click on the upgrade button on the railway when F4.
- Next thing you can do about supplies is changing your motorization priority: horse > single truck > double truck.
- Each increasing level provides more range to your supply hub and therefore providing more divisions with the supplies.
- You can do the same thing with changing motorization priority from selecting your general and looking next to his portrait.
- Wherever that army travels, the supply hubs will automatically increase their supplies for them.
- Another way of increasing supplies although is more of a last resort is by increasing infrastructure in the provinces where you want those supplies.
- Upgrading your motorization priorities needs you to produce trucks. At the start of the game have a few factories on Trains, Trucks and Convoys.
- Generals have the 4th stat that reduce supplies. And Logistics company reduce a division's supply cost by 10%.They're especially useful on divisions like tanks or large.
- A naval base acts as a supply hub, so in costal provinces it can really be worth it to build a naval base rather than a supply hub. They are 4 times cheaper than hubs.
8. Spies:
- Best practice is to pick a spy either with the Seducer trait or if that isn't available just pick a spy that has the most traits to him.
- Some nations have focuses that increase the number of spies particullary USSR.
- In the upgrades: Passive Defense upgrade makes it harder for the enemy to get intel on you and complete opperations and Interogations Techniques upgrade increases the chance of capturing an enemy spy.
- Just building an intel gives you a lot more intel on that nation: on the Intel Ledger.
- You can increase the percentage for each branch by researching the relevant upgrade on the top line upgrade tree.
- Having an intel network also provides combat bonuses for you and penalites for your enemy: +100% to naval invasion and increasing your planning speed, where as the enemy gets -100% max planning factor and -5 entrenchment.
- Moving the spies behind enemy lines can give you an advantage, particullary in defensive wars like USSR or China.
- Quiet Intel Network maintains your network level without actually growing it and also removes the risk of your spy being caught. However you lose combat bonuses.
- You can reduce the chance a spy will get captured with the S pills upgrade or Localized Training upgrade.
- S pills also has a chance of your spy unaliving itself rather than being caputred which saves having to wait a crazy amount of time for them to escape.
- If you have a spy of a different nationality, (which Localized Training upgrade increase the chance of) it reduces the chance of the spy being captured in that country and it also increases your intel gain. This is pretty much mandatory to spy on USSR.
- Boost ideology increase the ideology in your target nation, the stronger the network you have the stronger the gain will be.
- War Propaganda reduces the War Support and Stability on weekly basis on a given nation.
- Root Out Ressistance can be opperated in your occupied territories to reduce the ressistance in that state.
- Control Trade makes it that more of that nation's resources are available to you.
- Diplomatic Pressure allows you to slowly increase that nation's opinion of you. Pairing the Improve Relations with Diplomatic Pressure will open some options to you.
- Anti-Partisan, Diplomatic Training and Psychological Warfare upgrade can make these missions more effective.
- Opperation requires multiple spies and some equipment, one of the most powerful opperations is to steal blueprints by infiltrating army, administration etc.
- You'll have a chance to get a technology in that area that that nation has already completed or a research bonus in that area.
- Once Steal Blueprints is done you'll lose the infiltration so you'll have to complete the infiltration mission again and steal the blueprints once more.
- Invisible Ink and Blueprints Stealing upgrades makes you stealing blueprints opperations more effective.
- Communists and Fascists have another extra opperation "Collaboration Government" very expensive but very beneficial.
- It increases compliance in a nation once you capitulate them as well as reducing their surrender limit.
- You can do this very well with Germany on France and Poland as soon as you start the game.
- Another interesting opperation is Orchestrate Coup, to pull this off you need 20% your ideology in their nation as well as >70% stability for minors or >50% majors.
- After that opperation is completed a civil war will start.
- The bottom line upgrades affects the power of your cryptology.
- Once it's completed it gives you additional intel for that country as well as air detection too.
- And that's just the passive effect. You can also activate your decryption bonus which lasts for 30 days and increases your planning speed against that nation, decreases your naval invasion penalty and gives you a +15% defense bonus against them, and +15% breakthrough bonus against them.
- So it can be good to activate before a major push or if you're being attacked. But after that you'll have to decrypt again from 0.
- The last 2 right-side upgrades for crypto will completely reset the progress that other nations have on you, you can do them right before you start war.
- But don't do the last 2 right away, start with the ones on the left first just until the middle one. And save those on the right for just before you go to war.
9. General Traits:
- Winter Specialist and Winter Expect are terrible. Winter Specialist is only good to grind for the good Adaptable trait. The other terrain traits depend on the situation. They are nice to have, but the only reason you would go for them is to go to Adaptable. The best of them is Mountainner because montains usually give huge debuffs.
- Skiled Staffer is good but it's very difficult to go for it. Expect Delegator is exactly the same, even rarer than Skilled Staffer in fact.
- Trickster is average, only good because you can get what follows after him. Guerilla Fighter is good for defense, not very good as it doesn't actually increase your entrenchment just the entrenchment speed. But Improvisation Expert is good by contrast, just for that 10% speed and Makeshift Bridges with negates the negatives of small rivers, so go for that one instead.
- Organizer is terrible but if you want to make it a Field Marshal you need Organizer to work towards the good ones from the Field Marshal region.
- Panzer Leader is awesome for tanks. Panzer Expert is not that great because it gives you defense, you don't use tanks for defense. Combined Arms expert instead is awesome, because mechanized already have high defense to begin with and this gives an extra 15%.
- Cavalry Leader is underrated because it also gives you bonuses to Motorized which stacks with Panzer Leader. But Cavalry Expert is terrible.
- Engineer is bad, and it also leads to 2 other bad traits, so stay away from him. Fort Buster is nice but you destroy forts with bombers already. Scavanger is even worse as it only gives you 3%, if it were 10% that were something but 3% is too small to worth.
- Infantry Leader is S tier, the bread and butter, you are going to use infantry most of the time. It even leads to some good traits. Infantry Expert is very good as well, giving you an extra attack to infantry. Ambusher is very good as well, that +5 entrenchment is really really solid. Especially if stacked with Defensive Doctrine.
- Invaders is very difficult to grind. It's an okay bonus for naval invasion but just getting it is absolute nightmare. And then the 2 other upgrades are not that great.
- Commander trait is terrible. It doesn't give attack or defense for special forces. Just less supplies penalties, it's awful. It even leads on to some awful traits as well. Camouflage Expert is good if the enemy has air superiority, but it's very had to get Commander trait and you need that bad trait to get this one.
- So for Generals, the good traits are: Adaptable, Skilled Staffer (but you get it late game), Guerilla Fighter is average for defense, Improvization Expert is good for attack and slightly better than Guerilla because speed and rivers, Panzer Leader is very good for tanks, Combined Arms is a very good follow up, Cavalry Leader is underrated and very good, Infantry Leader is top tier, Infantry Expert is very good for attack, Ambusher is very good for defense, Camouflage Expert is good in the event that the enemy has air superiority but you have to take a Commander for it.
- Charismatic is very good, you recover your division's organization 10% faster when not in combat. Good on both defensive and offensive.
- Organization First is a very good replacement for the radio, it works on the attack and the defense, but there are some doctrines that make this worthless because the game will reinforce either way, so it's worse than Charismatic.
- Defensive Doctrine, very good if you are on the defense, very good for entrenchement.
- Offensive Doctrine, very good if you are on the offensive, to keep the momentum up and very good to stuck with other less org loss when moving traits.
- Aggressive Assaulter is amazing for tank divisions because of the Breakthrough bonus. Not so much of a benefit for infantry though.
- Unyelding Defender is good for a defensive trait but actually not that great, +10% defense is not that great for what defense actually is. Defensive Doctrine is better.
- Thorough Planner is good, it's one of those traits that if you have a free slot and are not waiting for Logistics or Adaptable, it's good to take.
- Fast Planner is completely useless, you never really need that extra planning because you have Staff Office Plan that gives 40% at the cost of some command power.
- Logistics Wizard is the big daddy and OP, even after it was nerfed, this is massive.
- So for Field Marshals, the good traits are: Charismatic, Defensive Doctrine, Offensive Doctrine, Aggressive Assaulter for tanks, Unyelding Defender if you already took the Defensive Doctrine slot, Thorough Planner if you have a free slot is good, Adaptive and the best Logistics Wizard.
10. How to play Air (start by reading 4 air doctrine before reading this one)
- At the start of the game press F3, select the air overview button on the top right, hold shift and select all air you have, then right-click on a central airport.
- Select the airport, then select "Merge all airwings".
- The best way to organize them is in sets of 200 planes for the airports.
- You can click on their number and increase or decrease their maximum number. Make all your airwings 200, of if you have let's say more than 200 Fighters, split them into 2 wings of 200.
- Hold left shift and press the exercise button and then they'll train up to level 3.
- The most important missions that you're going to use are: Air Superiority and Close Air Support (CAS) missions.
- Air Superiory means they shoot down any plane they see, fighters or bombers. This is the main mission you will use.
- However, if the enemy has a larger force than you, put your fighters on the Interception mission, where they only target enemy bombers not fighters and they only leave the airport when enemy planes are in the region. However, it doesn't provide Air Superiority in a region where as Air Superiority does.
- Close Air Support mission is carried out by your bombers. It targets enemy land units so enemy divisions and having good air support can make or break a play.
- Naval Strike is carried out in the sea regions to target enemy ships.
- Strategic Bombing will target enemy factories, infrastructure and other buildings. This can wear down and weaken your enemy over time and distract their airforce, taking them away from the front.
- To assign them a mission, select them, right-click on the region, then select the mission you want them to have.
- Another way to assign your air Wings that is easier is to just assign them to an army. Left-click on the army instead and select the mission. Now they will just automatically follow your army group around. And run those missions in the regions that your army is fighting in.
- Your Air Force is really there to support your army and navy. You want your own army to attack enemy divisions and ships, but you also want to protect them from being shut down and your enemy is going to bomb you too, so that's what you need fighters for as well as. To protect your own planes as well as stop and shot down enemy ones.
- There are 6 plane types: if you want to go just simple and straight-forward just build fighers and CAS.
- Some planes are more specialized: CAS, Naval Bombers, Strategic Bombers.
- One way you can play is have a mix of these and utilize them where they are effective.
- Another method is by only going the Tactical Bomber which is a jack of all trades. They are not as effective as the speciality planes, but it's just more simple to just build 1 class and then use it whenever necessary.
- Fighters are really essential to protect your own bombers from the enemy and shoot down enemy planes.
- Fighters are screens to your bombers as much as you have screens to your Capital ships in the Navy.
- Your Aircraft Carriers can't just take any planes on board, only the ones on the left after you research the carrier technology.
- Your divisions will benefit greatly from the support of CAS and having Air Superiority in the regions where battles take place.
- If the air region is shown as red or grey you need to move some fighters to combat the enemy planes.
- Your divisions will have a negative debuff if you lack Air Supremacy.
- If you have a hard time shooting down all the enemy bombers with your planes, try assigning AA support companies to your divisions, they will shoot down enemy planes that are carrying out CAS missions and are really good at it.
11. How to play Navy (start by reading 3 navy doctrines before reading this one)
Ok, so, recap:
- If you want lots of Battleships and Cruisers then Fleet in Being.
- If you only go for submarines then Trade Interdiction.
- If you're doing lots of Carriers and focus on them then Base Strike.
Each doctrine provies bonuses for each type of ships but again is specialized. (anything that boosts your fleet's organization and armor is important)
Now for the new stuff:
- When you organize your navy, if you merge all your ships together in one port and press the Balance button, it will split them up into task forces that are not only balanced but also have the right number of screening efficiency. It's even going to assign relevant icons by itself.
- At the very least for a ship design you need to have an engine and a primary gun
- Second slot is for Anti-Air which is going to increase your AA stat against any planes trying to attack the ship
- Then for 3rd slot you have Fire Control which gives bonus for your gun or AA; or Sonar which helps you detect submarines and engage them; or Radar which gives you more ability to detect and engage enemy surface ships.
- Next to the enginge is the secondary weapon which is your secondary batteries or for Destroyers you can add torpedo.
- And the final slot on the bottom is your armor which is for protection, make it less likely to be sunk in battle.
- The top slots have a lot of variety.
Navy Stats:
- Range: How far your ship can reach from the nearest base.
- Speed: gives a chance to catch an enemy fleet when they spot them and gives a chance to your ship to avoid enemy fire. (Speed is very important for ships; Agility is very important for air; for tanks speed isn't as important. Even for Air, agility is not as important as speed is for the Navy)
- ORG works exactly like infantry, how ready is to engage in a battle and how long is going to last in a battle.
- HP how much damage it can take before it's destroyed
- Manpower is only important because it affects how much Naval Supremacy or Naval Projection you are able to affect in a region with a ship. (submarines have low manpower)
- LIGHT ATK, LIGHT PIER; HEAVY ATK, HEAVY PIER, similar to the hard attack and soft attack of land divisions. If you imagine your screens are light and your capital ships are heavy. Light attack is only going to affect enemy screens. Heavy attack is only going to affect enemy capital ships. So light guns enemy screens. If you have a heavy battery you'll be able to engage heavy capital ships.
- DEPTH CHARGES how likely is it to engage and destroy submarines.
- ARMOR ability to avoid enemy attacks. If you have 10 armor and are a screen, an enemy is going to need more than 10 light attack or light piercing to do a decent amount of damage. So adding armor to you ships especially small ones can be a good strategy.
- ANTI-AIR is damage to planes, having a lot of AA in your ships is very good.
In importance: Speed > Armor > AA. (not set in stone, but general idea, attack is important too)
Modules:
- Smoke generators are very good, allows you to retreat
- Depth charges are good anti-submarines
- And sonar detects submarines.
- Airplane catapult gives both surface and subs detection
- Armor upgrade is self-evident.
On the support tab:
- You have light, medium and heavy batteries with different bonuses to light and heavy attack. (depending on what you go against)
- Dual-Purpose are interesting because they give you a smaller attack than normally would but also give you anti-air.
- You need to research the first torpedo tech for naval bombers.
- And then you have mines at the bottom. If you're real sneaky and mine the enemy coast with the submarines you'll do a lot of damage.
- Reseraching the AA in the military tab will also give you the next levels of naval AA.
- Reseraching radio tech also unlocks the radar next levels on the ships, which gives more detection both surface and subs and also increases anti-air.
12. Basic Navy Designs: (basically, division templates but for navy)
- Generally, try to use the best unlocked research tech possible.
- BASIC SUBMARINE: level 1 engine, level 1 torpedo tube. All you do is fill space for naval supremacy. Not good for anything else except convoy raiding.
- STANDARD SUBMARINE: level 3 hull: 3 submarine torpedo tubes, best engine you can, 1 snort for sub visibility makes him harder to detect.
- ANTI-SUB DESTROYER: at least lvl 2 hull, 2 best depth charges, cheapest gun possbile, best sonar you can get, best radar you can get, best engine you can get.
- SPOTTING CRUSIER DESIGN (works well in combo with anti-sub destroyer): at least level 2 hull, best radar, best sonar, 3 best airplane catapult. (huge amounts of surface detection and good amount of subs detection)
- BASIC DESTROYER: level 1 engine, level 1 gun. Very cheap, only good to get that 4 to 1 ratio for your Capitals.
- STANDARD CRUISER DESIGN (Light Crusier that's going to engage enemy screens and destroy them): level 3 hull, 2 medium batteries, best level of light armor, 1 fire system control, best engine.
- STANDARD BATTLESHIP: at least level 4, 5 Anti-Air, 1 fire control, 1 radar, 1 dual-purpose secondary, 1 highest armor. (all enemy planes will focus on this and get shut down)
- STANDARD CARRIER (make sure the production cost is less than the battleships so they are not targeted): 1 AA, 1 radar, 4 Hangars, best engine, (super powerful with naval bombers)
- Go to the Office Crops and get Naval Refit Years spirit, makes it 25% faster to refit ships. Remake every class to have the best modules you have, double-click on one of them and select "refit ship".
"Forget all your naval options and spam submarines" - Sun Tzu.
Seriously, if you don't want to bother learning all of this, just spam submarines, the AI rarely uses destroyers.
Navy Works like:
- 1 Admiral has a Fleet, each fleet has different Task Forces.
- When your fleet meets and enemy fleet they begin a naval battle.
- Each naval region has a certain amount of superiority depending on the strength of each fleet.
- The submarines spam is amazing for singleplayer is low effort, effective and pretty set and forget.
- Build a lot of cheap level 1 submarines. They are hard for AI to detect, they have cheap production cost, long range, decent attack.
- Their main weaknesses is naval bombers but the AI doesn't use it properly.
- Open F2 naval tab, left-click & hold shift on the theater tab, select all of them, then right-click at the bottom of the pannel to move them in reserve.
- Select all the reserve fleet and then click on merge. All the boats will come to 1 port.
- Double-click and hold shift on submarines to select all submarines only.
- Select the submarines and assign them to an Admiral.
- Press the "split the selected task force in half" until you have 10 different task forces.
- Select each task force reinforcer button, and put a number like 15-20. Give it a name, and save, that creates a template for a task force.
- Then for each other task force assign the template you just created. When a new submarine is built it will automatically join a task force that is under strength.
- Activate "Automatic split-off" when one of your boats gets damage it will return to the port to repair individually.
- Select your Admiral and right-click on all of the regions you want the Task Force to move in.
- Assign "Convoy Raiding" mission.
- The other metod to run your navy is to go all out with surface fleet of battleship, cruisers and aircraft carriers.
- Capital ships (Carriers, Battleships, Battlecruisers, Heavy Cruiers) sink enemy vessels in naval combat.
- Screens (Light Cruisers, Destroyers) are there to protect your capital ships.
- You should keep at least a 4 to 1 screens to capital ships ratio to protect your capital ships.
- Destroyers are good at anti-submarines when upgraded with specific stuff. And also good at spotting enemy ships (putting them on patrol missions; with your main fleet on strike force missions - what this means is when operating in the same sea region your main fleet will only leave port to engage enemy sheeps when your destroyers find them; drastically cutting down fuel usage)
- Adding fighters to a sea region reduces the chance of being naval bombed.
- To naval invade: select "naval invasion" mission, select left-click from where you want to invade, right-click where you want to invade. You need naval supremacy in the region to invade. Take region with a port to have supplies when you land.
- For ships, give them mission "Naval invasion support" will provide them extra naval supremacy as well as naval bombardment from your ships.
- Make sure you also have convoys for transport. Marines give you a bonus to naval invasion, normal troops take a penalty.
Done!
See? Hearts of Iron 4 is not that complicated.
In all seriousness now, is you learn the basics then this ^ it will save you 300 hours of gameplay worth of skill. It's not everything, but it's enough to turn you from a rookie to an advanced player in no time. And if you played CK3 or EU4 then you already have the hang of it.
