Thank you TruckerBarry9493 for helping with the guide in the tank section!

Creating divisions is one of the most important aspects in mastering Hearts of Iron IV. In this guide, you’ll be shown what division templates are the most optimal. In addition, combat width, reliability and support companies are discussed in detail.

To design a template, you will first need army xp to edit templates. Early in the game, army xp is earned by advisors, whereas typically most of your army xp comes from your divisions being in combat. This means it is wise to send volunteers to foreign wars in order to earn army xp! Wars you can send volunteers to are the Spanish Civil War and the (second) Sino-Japanese war. In addition, send an attaché to get some of the army XP the country you're supporting earns.

To create a division, go to the tab ‘recruit and deploy’, then click “edit” on any division. This allows you to edit any division of your choice. To create a new one, click “duplicate”, choose a name for your division, then click “save”.

This division is set as ‘elite’; it will receive the newest equipment first and will always be supplied first.

Playing as e.g. the USSR, we only have a limited number of factories available with which to supply guns to our infantry divisions. This means our design should be cost-effective; we want to maximize the damage we deal relative to the damage we take. Note that as the USSR, we have more than enough manpower; factories are the limiting factor in building up the red army!

A quick summary on designing divisions:

• A division consists of 5 combat regiments and 5 support companies.
  
• A regiment (vertical column) can only hold batallions of its type (e.g. the ‘infantry’ category).
  
• It costs 5 army xp to add or remove a batallion, and 10 army xp for a support company.

The stats of a unit are displayed when editing a unit in the template designer, and the current stats of a division in the field can be inspected by clicking on their icon.

The game divides combat stats in 3 categories; Base stats, Combat stats and Equipment cost.


Organization – The health of your division. When this runs out, your unit will flee to a friendly province when being attacked, or stop their attack when attacking. Organization is regained over time.
Max Speed - The speed at which your units move in the field. Typically, your unit’s actual speed is lower than this value. For example, if your unit walks through mountainous terrain, their speed will be reduced significantly. The Max Speed is determined by the slowest battalion in the division.
Recovery rate – The speed at which you regain organization outside of combat.
HP – Shows what percentage of equipment (and manpower; whichever is lowest) your division has left. The lost equipment and manpower will be automatically refilled using equipment from your stockpile, as long as you have any left. Note that for every 1 ORG lost in combat, 0.5 HP is lost. The same goes for damage taken by CAS.
Supply use – Determines how much supply your units use. Units with insufficient supply will have their various stats reduced.
Reliability – Tells you AVERAGE reliability of all equipment in division, which determines recovery rate. Attrition losses are determined by reliability; see the reliability section for more info.
Reconnaissance – Your total recon value is equal to: total recon = (general skill level+recon). When your total recon is higher than the enemy’s, you have a chance to counter the enemy’s tactic. Assuming equal skill levels, your odds of picking a counter increase by +165% (which isn't much, as discussed later!) See the list of tactics here: https://hoi4.paradoxwikis.com/Combat_tactics Tactics guide[docs.google.com]
Exp. Loss – Determines the amount of xp a division loses when taking HP damage. When fighting, the amount of xp gained typically outweighs the amount of xp lost. Xp increases a unit’s soft attack, hard attack, defense and breakthrough by 25% (trained), 50% (veteran) and 75% (elite).
Trickleback – Determines the amount of manpower that is regained when losing manpower.
Weight – Determines the amount of convoys (transport ships) used when transporting troops over sea.
Suppression – A stat that is only used by garrison battallions (not for deployed divisions). Cavalry has very high suppression values.


Hardness – Determines the ratio of damage that is taken from soft attacks and hard attacks.
Soft attack – The amount of damage you deal to enemy divisions. Virtually all units have low hardness, so soft attack is more important than hard attack.
Hard attack – The amount of damage you deal to armored divisions. Heavily armored divisions typically have up 65% hardness. The exact formula for damage done is:
Net attack = (1-hardness)*soft attack + hardness*hard attack.
Breakthrough – When attacking, this reduces the damage you take up to the enemy’s attack by a factor 4. Having more breakthrough than the enemy has attack has no effect. Only tanks have high breakthrough values.
Defense – When defending, this reduces the damage you take up to the enemy’s attack by a factor 4. Works like breakthrough, but for the defender’s side. Infantry has a high defense value.
Combat width – Determines how many units can fight in a battle at once. The maximum combat width is determined by the terrain you’re fighting on. When combat width is exceeded, your units receive a small penalty to soft attack and breakthrough/defense.
Armor – When your armor is higher than the enemy’s piercing, you deal +50% organization damage and get -50% organization taken. When the enemy’s piercing goes to 75% of your armor the aforementioned bonuses will scale down linearly to +0% organization damage and -0% organization damage taken. (This 'partial piercing' mechanic is currently broken, piercing currently works binary and is yet to be fixed!) The armor of a division is calculated as 30% of the highest armored battalion plus 70% of all divisions’ average armor.
Piercing – See armor. The piercing of a division is calculated as 40% of the highest battalion piercing plus 30% of all divisions’ average piercing.
Air attack – Reduces the damage you take from enemy Close Air Support (CAS) by up to 75%, and shoots down enemy CAS attacking your division. The maximum damage reduction is already achieved at 10.7 air attack, so putting in 1 Anti-air support company (15.2 Air attack) will do the job.
Entrenchment - Increases max. Entrenchment, which grants 2% to defense and soft attack for every 1 point of entrenchment. Moving a division removes this bonus. When a unit is standing still in a province, entrenchment builds up slowly up to the maximum entrenchment.
Coordination (Hidden stat) – Increases the ‘focusing’ of all your divisions on a single enemy division. Having high coordination will quickly overwhelm the targeted enemy division, forcing them to retreat. Is increased by signal company.
Initiative – Slightly increases the speed of battle planning. Also slightly increases reinforcement rate and coordination. Out of these three, coordination is the most important stat (and only buffed slightly), so initiative is typically not very useful.

The rightmost tab summarizes the equipment that is needed to field a division. Manpower is drained from your manpower pool, and equipment is taken from your equipment stockpile.

The 'max Speed' is just the base speed of a division; when travelling, this number is typically lower due to various modifiers.

First, every terrain type has their own 'movement cost' modifier. This means that even though a distance on the map might look small 'as the crow goes', in reality the traveled distance is much greater.

Second: Weather, rivers, being low on ORG, low supply, low infrastructure all lower your division speed, whereas Recon company, Engineer company, Mobile Warfare, advisors, increase division speed, all additively. Battalions can either give a positive or negative movement modifier. These modifiers often matter more than the base speed of a division!


It turns out that recon can be a little bit more than 'just 10%'. If you have some particularly bad total penalties like -80% so you only move at 20% speed, adding +10% to that is adding +50% more speed than you had before.
- CorpseFool

The minimum speed at which your divisions travel is capped at 1 km/h.

Reliability is quite important. It affects equipment losses due to attrition and also reduces your movement speed when walking through various terrain types. For tanks divisions, you'll even recapture ('repair') some of the tanks you've lost during combat! Therefore, we would like to keep our reliability high. The reliability of infantry equipment and support equipment cannot be changed, but some equipment types such as tanks have customizable reliability, This chapter will focus on the (un)importance of reliability.


Even when your troops are not fighting, they can still suffer from attrition. This represents the real-life difficulties when fighting in rough weather, having nothing to eat, or having no ammo left. Your units suffer from attrition when;

• Not having enough supply.
  
• Moving (also attacking) to ANY province in bad weather or bad terrain.

To prevent terrain and weather attrition damage, make sure to supply your troops and don’t attack during snow storms or a province covered in mud. Avoid attacking into mountains, deserts, jungle and marshes if possible.

The equation for calculating attrition losses can be found on the wiki: https://hoi4.paradoxwikis.com/Attrition_and_accidents

Losses can be very high if reliability is too low!

This graph tells you too not worry about reliability when the number of equipment is low.
For example, a light flame tank company only requires 30% reliability, since it only requires 15 light flame tanks.

Instead of designing your divisions to have high reliability, it is better to simply avoid attacking in Mud, Snow and mountains.

Units that require fuel consume fuel when moving. When in range of supply (see next section), fuel automatically gets refilled. Transport planes do not provide fuel. When out of fuel, your units lose 90% (!!) of their combat stats and suffer from -40% speed. Non-motorized divisions do not suffer from fuel penalties. Keep in mind that army fuel usage is quite significant.


Having adequate supply is vital to keeping your units happy. Without sufficient supply, your units will suffer from:

• Attrition
  
• Decreased movement speed
  
• Decreased soft attack, hard attack, breakthrough and defense.

Supply emanates outwards from your supply hubs. The further a province is from a supply hub, the lower supply it receives and passes to the units standing on that province. Supply is also provided by local infrastructure and population (large cities), but their contribution to supply is quite small.

Supply hubs only provide supply when connected to your capital; connection can be established via harbors or railroads. On land, railroads take some time to repair, which punishes players who advance too far into enemy territory too quickly. A good workaround to this is using air drops for extra supplies.

Supply is easy to manage;
- Put your marshals on 'supply by truck'
- Use transport planes for air drops.
- Have enough trucks and trains available.
- Armored trains don't take any damage from enemy Logistics Strike.


Make sure to have enough trucks and trains in supply by hovering over the supply icon.


Click this icon to have your armies be supplied by trucks instead of horses.

There are many battalion types in the game. In this section, we’ll list the most-used types.


Infantry - The most used battalion in the game, which is also the cheapest battalion. Infantry is best used to halt the line against enemy attacks, since they have decent soft attack and defense for their cost. In addition, they add a lot of HP to your divisions, making them very durable. Due to their low breakthrough, they are ill-suited for attacking.
Artillery – Artillery can be found in all kinds of divisions. Artillery has a very high soft attack value, but low values in all other categories.

Rocket Artillery – Virtually identical to artillery, but is unlocked later in the game (1940).


Cavalry – Faster than infantry, but uses much more supply and is a bit more expensive. Their only strength lies in high suppression. Use these only for garrison battalions!

Motorized Infantry – Virtually identical to infantry, but 3x as expensive and uses fuel. Contrary to infantry, it has high breakthrough compared to infantry, making them better at attacking than infantry. In addition, Motorized infantry has a high maximum speed (12 km/h), making them perfect for performing encirclements. Note that these do use fuel; having too many of them will run your fuel supply dry!
Motorized Artillery – Same stats as artillery, but has a high max speed (12 km/h).


(Medium) Tank – Due to the tank designer introduced in the No Step Back DLC, tanks can be designed however you wish, and the role of tanks can vary widely. In general, tanks have high armor and breakthrough, making them excellent at offensive operations.
Tank destroyer (TD) – Tank destroyers function to add both piercing and armor to your division.

There are plenty of other division types available, but these are in general not worth getting or too niche to see any use. An honorable mention is paratroopers; when dropped on enemy supply hubs, these can cut off supply for a while, weakening their front line.

You can add up to 5 support companies to a division. Support companies are typically very cheap and provide strong bonuses to your divisions.

Tierlist as created by Cloak71. Outdated, but I'll leave it here.

Support Artillery. Very cheap and gives a good amount of soft attack, and does not use any combat width. Include these in any division type.
Support Rocket Artillery. Gives the same bonuses as artillery company, but is unlocked very late in the game.
(Assault) Engineer company. Not too expensive and gives a wide range of bonuses to attack on various types of terrain, movement speed and most importantly, entrenchment.
Anti-air company. A single Anti-air company can reduce incoming CAS damage by up to 66%! Very strong when the air area you’re fighting in is contested or hostile. Also grants piercing.
Medium Flame tank company. Increases your soft attack and breakthrough when attacking in various types of terrain, while being quite cheap. Always add them to your offensive divisions.
Support Anti-tank. Adds enough piercing to your division to counter an enemy armored division.
Maintenance company. Increases reliability of ALL equipment by 5%, by an additional 5% with the 1939 technology. Effectively reduces Infantry equipment losses due to attrition by a factor of 10 in 1939 (90% reliability->99% reliability), or a factor of 2 for trucks (80% -> 88% reliability) Note that this works best for equipment your division requires a lot of, like trucks and infantry equipment. Very strong when facing lots of attrition, especially on equipment with high base reliability (e.g., infantry equipment).
Recon companies. Adds recon to your division, increasing chances of countering enemy tactics. Assuming equal general skill levels, counter-tactic weights are multiplied by 1+(5*0.35)= factor 2.75. But many tactics don't have a counter, and the weight of all other tactics combined is much more than this 'enhanced' counter tactic weight; increasing a low weight by 2.75 is still a low weight. This stat sounds better on paper than it is in practice. Another effect is adding additive speed on virtually all terrain types to your batallion.
Logistics company. Causes your units to use less supply and less fuel. Very good in offensive divisions, as those divisions use lots of supply and fuel. Lower supply usage allows higher concentration of force.
Field hospital. Grants trickleback and reduced experience loss on casualties, also adds HP to divisions. The XP loss reduction on casualties is very good for gaining/maintaining division veterancy.
Signal company. Grants initiative, which slightly boosts coordination. Initiative also significantly boosts reinforce rate.
Military police. Grants +20% suppression. Pays back for itself on garrison divisions with 5 cavalry or more.

Decreasing enemy stats is quite simple; a fleet on 'hold' command (or the 'naval support' mission) will fire at enemy divisions fighting on a coastal tile, giving them a up to -25% debuff to soft/hard attack and breakthrough/defense in combat.

Similarly, a railway gun will also bombard enemy troops, but from a train. It will affect every enemy division in its radius, giving a -10% (-15%, using the 'Elevated Engineering Corps' Spirit of the Army) debuff in soft/hard attack and breakthrough/defense to enemies.

The easiest way to use railway guns is to attach them to an army; they will follow that army anywhere they go. They are a cost-effective investment for major nations, but smaller countries should invest in building more divisions first.


Assign your railway gun by selecting it, then clicking this button.


A railway gun in action.

Link to the Combat Width Calculator

[github.com]

https://github.com/Vezachs/hoi4-combat-guide/blob/main/combatwidth.py

The optimal division combat width depends on the terrain you’re fighting on, since you receive penalties when going over the maximum combat width. Since your units will be fighting on many types of terrain, we have to find a compromise between fitting in the combat width and a division’s IC cost. Units smaller than 10 width receive a combat penalty, so we will not consider divisions smaller than this size. Smaller divisions are also more prone to being ‘focused down’ due to the coordination mechanic, which also decreases small divisions’ strength.
Summarizing, optimizing your divisions’ combat width will depend on both how well your units fit in the terrain, along with their cost per combat width.


TLDR; Every CW has roughly the same CW penalty. Look at the graph to find a local optimum, but it doesn't matter that much.

Going over the maximum combat width gives an attack penalty. The exact formula for combat width is given on the wiki: https://hoi4.paradoxwikis.com/Land_battle.

I have created a handy tool to calculate the ‘combat effectiveness’ fighting in various terrains by multiplying the total attack of your divisions by the combat penalty they receive. The 'overstack penalty' is also included, and the province type and number of attacking provinces is accounted for and can be changed manually. The link to this simulator is found in the download section.

Best CWs for combat in Russia

For combat in Russia, 35 CW is the last width which doesn't take hefty penalties. Go for 35 CW when going for tanks.

Best CWs for combat in North Africa

For combat in the North Africa, 35 CW is by far the best CW. Go for 35 CW when going for tanks.


Pros of small divisions
- Very high ORG per combat width.

Cons of small divisions
- Support companies make up a large part of its cost.
- Needs lots of generals.
- Takes more losses due to coordination mechanic. (see 'defense' and 'breakthrough'). These losses also reduce XP gain.

Pros of large divisions
- Doesn't require many generals.
- Takes fewer losses due to coordination not affecting this division much.
- Support companies are relatively cheap.

Cons of large divisions
- Very low ORG per combat width.

To weigh the advantages of small divisions VS. large divisions, the following test was performed.
The small division has a CW of 10, the large division a CW of 30.

Large divisions attacking small divisions.
Small divisions attacking large divisions.

Even though Poland (10W) wins offensively and defensively, on the offense Poland takes many more losses.

From the graph above, we conclude that even though Poland produces better combat results wins both when attacking and defending; their losses are much greater when attacking. Furthermore, their greater losses reduce their veterancy; they lose XP when attacking, whereas the German units gain XP even when attacking. Note that the only difference between the attacking and defending side is that the defending side has the bonus of entrenchment, which makes then a bit stronger.
You might ask: how can these results be explained? As said before, due to coordination, the smallest division gets focused down first. Once the first (small) division falls, Poland has fewer combat width in use, decreasing their total damage. For Germany, this happens too, but much later on since for them, 1 division getting focused down is still 1/3rd of their total combat width, whereas Poland gets 1/9th of their combat width focused at.

In addition, HP of a division is also important. Small divisions have low HP, which means their damage output significantly decreases during combat, since ORG losses are the same as strength (HP) losses in combat. This means small divisions deal relatively little damage compared to the damage they take.

CLarge (e.g. 30W) divisions should be used for attacking as they require more support companies. (Support companies become more effective for larger divisions.) Smaller divisions are better at holding the front line than large divisions.

When designing a division, it is important to keep combat modifiers in mind. All units have similar defense modifiers, but combat modifier values differ significantly for attacking. This is an additive bonus on top of the standard terrain modifier. E.g. Mountaineers with +30% attack in mountains receive a
-50% + 30% = -20%
combat penalty (to soft/hard attack and breakthrough) when fighting in mountains. However, you also want to use tanks when attacking for their high breakthrough, which do not have good mountain terrain modifiers. In practice, there are no good divisions for attacking in mountains. For river crossings and marches, you should use Amphibious Tanks.

This division has a 33.3% bonus attack over rivers.


For infantry divisions, we are mainly looking at soft attack and organization. Infantry has very high defense already, so maximizing soft attack/organization is the most important.

This graph tells that 22% of the divisions should be artillery and the rest infantry, disregarding damage dealt by CAS and support companies. Note that: combat strength= org*damage : Double the org results in double the strength, and the same logic applies to doubling soft attack.

We can conclude from this graph that it is best to put some artillery in your divisions, but not too much. Note that when there is a lot of CAS (which deals direct ORG damage), infantry becomes superior to artillery, since you will need org to survive CAS bombings. Turned around, when you CAS bomb the enemy, you'll also need more org, as this allows you to stay in battle for longer, letting CAS deal more damage. In addition, support companies also lower your ORG, so this also lowers the ideal artillery/infantry ratio.

For optimal combat power, less than 22% of your divisions should be artillery. 4 Infantry and 1 artillery gives an artillery ratio of 20%. However, support companies also reduce your ORG, so the ratio of artillery should be even lower. As a rule of thumb:

For every 6 infantry, include 1 artillery.

There is also a rule of thumb for tank divisions:
For tanks, the keep ORG above 30.

Using the calculator for optimum combat width (see Downloads), we find that for Eastern Poland, Plains: 17, Forest: 25, Marsh: 11, Urban: 3 provinces.
Putting this in the combat width simulator yields the following graph:

Optimal combat width in Eastern Poland.

We want the division to be as large as possible to ensure cost-effectiveness and reduce losses; however, smaller divisions can stay in combat longer due to their high org. This is tradeoff that has to be considered: cost-effectiveness VS fighting capability. This means the optimal combat width depends on where you want to place this tradeoff. Many players opt for a division width around 19 Combat width (with Artillery, Engineers and AA), OR a 10 Combat width (with support artillery).

For support divisions, we will want:
Artillery support: it does not use combat width, is cheap and provides lots of soft attack.
Engineer Company: Provides numerous combat bonuses.
Anti-air: Reduces air damage taken by 75%.
Anti-tank (mounted on a tank battaalion): Only when the enemy has tank divisions.

Keep in mind that due to support companies, smaller divisions are less cost-effective due to a large part of their budget going to support companies.

As a final note: In general, small combat width divisions take larger HP losses than large combat width divisions relative to the damage they deal, due to the coordination mechanic, where divisions focus a large part of all attacks on a single battalion. Smaller divisions do stay in combat for longer, as they have high ORG per combat width.

Fighter Aircraft have 3 purposes;

• Granting Air Superiority.
  
• Disrupting enemy support planes (and protect allied support planes)
  
• Killing enemy planes efficiently.

Cheap planes fulfill the first 2 goals, but are not good at killing enemy planes efficiently; both cost and K/D ratio matters for cost-efficiency.

Testing methodology: Let 100 planes fight enemy planes of equal total cost. The only requirement is that every fighter has a minimum range of 850km.

The way combat is resolved is quite complicated (see wiki), so tests were performed to find the best design. In general, you want a healthy balance of Air Attack, Air Defense and Agility, while having a good range.
Many designs were tested, e.g.: Small Airframe with Heavy Cannons, Medium Airframe with Heavy Machine gun, with armor, without armor, etc. The optimal fighter design can be found in the Aircraft Design section. Let me know if you can find a design that beats the current one!


A good CAS-plane aims at maximizing:
1) Land Combat Damage per plane (medium airframe CAS)
2) Land Combat Damage per cost (small airframe CAS)

Since production output is almost always a bottleneck, I recommend using small airframe CAS.

Reducing CAS losses

A few enemy fighters will always slip through your fighters and kill some of your support planes. Assuming all allied planes are equally visible, the number of CAS targeted by enemy fighters is determined by the proportion of CAS compared to the total amount of allied planes. This means it's impossible to prevent allied CAS from being shot down. To reduce the amount of CAS lost to air combat, the best stat (agility is typically 1 due to ground attack weapons) to increase is Air Defense: The amount of planes lost scales directly with: Planes lost ~ 1/(Air Defense).

This means that doubling the defense will halve the amount of planes lost. Max. Speed and Agility also reduce losses, but these are difficult to increase for CAS planes: Increasing defense via modules is much easier.

Decreasing disruption of your CAS

Speed, attack and defense reduce the enemies' disruption of your CAS missions; however, if you find your planes are getting disrupted frequently, you should build more fighters, as these counteract disruption much more efficiently than the CAS themselves.


CAS bonuses

CAS is essential to win wars.

• CAS deals damage directly to enemy divisions in combat.
  
• CAS gives your divisions a up to 25% bonus to attack and defense/breakthrough.

Air superiority bonuses

Having planes in the air increases your 'air superiority'. Most planes provide 1 point of air superiority, with some exceptions.

• Up to -35% defense/breakthrough to enemy divisions.
  
• Up to -30% movement speed to enemy divisions.

These penalties depend on the number of both friendly and enemy planes. These penalties are reduced in certain terrain types (much like direct CAS damage also has reduced damage in some terrain types).

The air superiority penalty depends on the % of Air Superiority you have: 25% air superiority (red air) means 17.5% Air Penalty to you. Only 121 planes are needed to achieve 35% superiority (if the enemy has no planes).

CAS is vulnerable to being disrupted and shot down by fighter planes. To keep your airspace safe, you’ll need to build fighters, which hunt for enemy fighter planes and shoot down enemy CAS.
In general, you'll want as many factories on planes as you can, since the direct damage dealt by CAS (both to ORG and HP) is extremely high.


You'll generally want enough fighters to disrupt all enemy support planes and prevent all disruption happening to your own planes. As a rule of thumb, you'll need at least 1.5 times as many fighters as the enemy to fully disrupt. If you start out with fewer fighters than the enemy, don't worry: a good fighter design will ensure you gaining air superiority in the long run!


Radar gives you more air detection, which directly increases the damage dealt by your planes. Air detection also increases disruption of enemy bombers! Therefore, build enough radar such that you have (full) radar coverage over the air zone you're fighting in.


Besides CAS and fighters, other plane types exist.

• Naval bomber/Patrol: Bomb and kill enemy ships (much more cost-effective than building your own ships!).
  
• Heavy fighter: These typically have more range and damage than fighters.
  
• Tactical bomber: Can be outfitted for any role, but is best used as CAS.
  
• Strategic bomber: Destroys enemy buildings, e.g. military factories. For an effective bombing campaign, you’ll need at least 1000 of them, as the auto-repair of buildings can be too great to overcome.
  
• Scout plane: Provides intel on enemy troop compositions. Since intel is are not that good, don't bother building them.
  
• Transport plane: Deploys paratroopers and drops supplies. Very important when pushing into an area where supply hubs are far apart. Putting 2 factories on transport planes should be sufficient for your logistical needs.

Airplanes can perform a variety of missions. When multiple missions are selected, missions are performed from left to right, i.e. Close Air Support is performed before Logistics strike.

• Pilot exercises. Very important! Trains your pilots, massively increasing the stats of the planes in the air wing, at the cost of some accident losses and fuel usage.
  
• Air superiority. Engages enemy fighters and shoots down enemy CAS/bombers. Grants air superiority, lowering enemy defense/breakthrough. Typically better than the interception mission, unless you're very low on fuel.
  
• Close Air Support. Deals damage to enemy divisions on the ground.
  
• Interception. Similar to air superiority, but stays on the ground if no enemy bombers are active to conserve fuel.
  
• Strategic bombing. Bombs enemy buildings to cripple their industry. Since buildings auto-repair, you'll need an air fleet of ~1000 Strategic Bombers to comfortably out-damage their auto-repair.
  
• Naval strike. Bombs enemy ships. Very cost-effective way of killing the enemy navy.
  
• Port strike. Has to be performed in the land area on which the port lies. Destroys ships that lie in port.
  
• Naval Patrol. Searches for enemy fleets.
  
• Logistics strike. Destroys enemy trains and supply trucks. Eventually, this will cause enemy units to have insufficient supply and suffer from attrition.
  
• Air supply. Drops supply from the air to units without supply, preventing attrition to your units.

Tanks got reworked as of 12-06-2022! Tanks are much better now; section will be updated as soon as possible. Armor stacking seems to be an excellent strategy now.

The amount of piercing you need depends on the quality of enemy armored divisions: you want your piercing to be higher than the enemy armor. At the same time, make sure your armor is ideally 2x the enemy's piercing source The AI's divisions are poorly designed; including an Anti-tank support company in your division will be enough to pierce those divisions. For multiplayer, players will build higher quality tanks and including anti-tank will not work.

Kesselschlacht by Waterdose.

To truly excel at Blitzkrieg, use tanks to break through the enemy lines, then use small motorized divisions (e.g. 14W) to take over undefended provinces and defend them, eventually encircling the enemy army and destroying it ('Kesselschlacht'). This is the most common strategy to destroy a large part of the enemy army.

Alternatively, you can try to 'overrun' enemy troops. When you enter an enemy province a unit is retreating to, that unit gets destroyed. Overrunning is best achieved by lowering enemy movement speed (having high air superiority) and having high movement speed yourself. This typically only works against a weak enemy.

• Even though tank divisions are excellent are attacking, you will want to spend the majority of your production capacity on planes, since without planes any offensive will be hard to execute.
  
• Light tanks have virtually no armor and a low cost. Medium tanks have good armor and low cost. Heavy tanks are similar to mediums, but have low speed, the same armor and higher breakthrough, but very high base cost. Medium tanks typically offer the best of both worlds.
  
• Aim for 30 ORG or higher when designing your tank divisions.
  
• Breakthrough only needs to be as high as enemy soft attack (per combat width). Excess breakthrough is useless, but luckily breakthrough is a cheap stat.
  
• Maintenance company (1939 upgrade) adds 10% to the equipment's reliability, e.g. 90% -> 99%. Make sure your tanks have at least 80% reliability, preferably 90%.
  
• Tanks have a high supply usage, logistics company reduces their supply usage significantly. Especially important in Multiplayer where front lines have many units in them.
  
• Amphibious tanks have terrible armor, which makes them unusable. However, normal tanks with amphibious drive are excellent, as have the same armor and also bonuses for attacking over rivers.

Your generals can be assigned to fight as volunteers in e.g. the Spanish Civil War. This will grant them the opportunity to farm traits.

Look at all the traits!

• Hover over a trait to see the requirements for gaining XP towards it. Some descriptions are not clear. For Trickster, you need to be 'flanking' (attacking from 3 directions). For Panzer/Cavalry leader, 60% of the divisions under the commander need to be of this type. This does not mean these divisions have to be in combat; you can technically use infantry to grind Panzer Leader.
  
• Your general gains trait XP for ALL eligible traits. For example, when attacking from 3 sides using tanks in Mountains, over a river, you gain trait XP for Trickster (flanking an enemy), Panzer Leader (using tanks), Mountaineer (fighting in mountains), and Engineer (Attacking over a river).
  
• The base trait XP gain is very high. You gain 0.45 trait XP per hour, per division. Encirclements and overruns grant 35 XP per division killed.
  
• The trait XP gain quickly goes to 10% of the base gain, within 30 hours (note that the Wiki might be wrong on this). (scaling linearly, 0.03 per hour). By resetting your attack every couple of days, the timer is reset, allowing you to earn much more XP. Joining an ongoing battle will put your units in the reinforcement queue; make sure to attack a province that is not under attack already.
  
• If you deal x as much damage as the enemy, you gain a 4x multiplier on trait XP earned. This is a scaling effect, which goes up to a 4x multiplier if you deal 4x as much damage as the enemy. The damage ratio is probably your division's attack, compared to the average attack of the enemy divisions. To have a division deal as much damage as possible, increase their combat width!
  
• Trait XP gain is reduced for every trait you already have. XP gain is reduced by 1/2 for 1 trait finished, 1/3 for 2 traits finished, etc. Get the traits you want to 98%, but don't finish them! You will also gain trait XP while being attacked, some be careful. Once you have all the traits you want, finish them.

Using these tips, it is quite easy to give a general of your choice the exact traits you want. Gaining all traits you want shouldn't take more than a couple months!

The most important traits:

• Adaptable
  
• Improv. Expert
  
• Panzer Leader.
  
• Cavalry Leader.
  
• Logistics Wizard, Field Marshal only.
  
• Any terrain trait.

Regarding Panzer Leader/Cavalry Leader: A tank division that contains 55% tank batallions, and 45% Mechanized Infantry, gains 55% of the Panzer Leader bonuses, and 45% of Cavalry Leader bonuses.

• Tanks are very expensive, build planes first. Pushing with infantry and CAS often works against a weak enemy. Only start building tanks when you have achieved full air superiority!
  
• Tank designs before 1940 are not included; their design should be similar to the designs listed below. Design tip: maximize soft attack and breakthrough.
  
• Heavy tanks are much more expensive than Medium Tanks, and suffer from very harsh combat penalties in many terrain types. They have become even worse after the piercing buff.
  Therefore, they are not included here.

Brick AA (1940)


Weapons

• One man turret (Cheapest turret)
  
• Basic Anti-air Gun (requires only 36 units in a batallion)
  
• Sloped Armor
  
• Armor Skirts

Modules:

• Bogie Suspension (Cheapest suspension)
  
• Welded armor (high armor for good cost)
  
• Gasoline Engine
  
• Engine: 0 points
  
• Armor: 14 points

Design explanation:

This design is an Infantry Tank! Make sure to use an equipment tag (e.g. the turtle, since this is slow). You should use this in armored infantry divisions. Their only function is to add armor to infantry divisions at a low cost. AA requires fewer units per division, and is as such cheaper than medium tanks. Very good in Single Player. Watch a video on them here: Youtube Link

Space Marine Tank (1940)


Weapons

• One man turret (Cheapest turret)
  
• Medium Howitzer (Highest soft attack)
  
• Sloped Armor
  
• Armor plates
  
• Radio III

Modules:

• Bogie Suspension (Cheapest suspension)
  
• Welded armor (high armor)
  
• Gasoline Engine
  
• Engine: 0 points
  
• Armor: 14 points

Design explanation:

This design is a Space Marine Tank! You should use this in so-called 'space marine' divisions. Their function is to add armor AND breakthrough to Special Forces. These are quite expensive, but you will not need many of them.


Medium Tank (SP) (1940)


Weapons

• Three man turret (Highest breakthrough)
  
• Medium Howitzer (Highest soft attack)
  
• 2x Heavy Machine Gun (for soft attack)
  
• Easy maintenance (increased reliability, 5% reduced production cost)

Modules:

• Bogie Suspension (Cheapest suspension)
  
• Riveted armor (Cheapest armor)
  
• Gasoline Engine (gives extra speed)
  
• Engine: 4 points
  
• Armor: 0 points

Design explanation:
Against the AI soft attack is most important, so this design stacks as much soft attack as possible. Its speed is 8 km/h to keep up with mechanized. This design does NOT stack breakthrough, since the base value from the turret will more than enough against the AI; having more breakthrough than the enemy has attack has no effect! The same applies to this tank's armor value. You'll be able to field 34% more of these compared to the MP tank variant because of its lower production cost.

Medium Tank (MP) (1940)

Weapons

• Three man turret (Highest breakthrough)
  
• Medium Cannon (Highest soft and hard attack)
  
• 2x Heavy Machine Gun (for soft attack)
  
• Easy maintenance (increased reliability, 5% reduced production cost)
  
• Advanced Radio (increased breakthrough)

Modules:

• Christie Suspension (Increased speed)
  
• Riveted armor (Cheapest armor)
  
• Gasoline Engine (gives extra speed)
  
• Engine: 8 points
  
• Armor: 14 points

Design explanation:
This design is more suited Multiplayer (when facing quality divisions). It has a healthy mix between Soft Attack and Hard Attack, making it perform well against enemy tanks. Breakthrough is maximized, to ensure that your breakthrough will exceed enemy attack.

Tank Destroyer (SP&MP) (1940)

Weapons

• Medium fixed superstructure (Required for cannon)
  
• Improved Heavy Cannon (Highest piercing)
  
• Squeeze-bore adaptor (more piercing)
  
• Easy maintenance (increased reliability, 5% reduced production cost)
  
• Sloped Armor (more armor)
  
• Armor Skirts (more armor)

Modules:

• Christie Suspension (Increased speed)
  
• Riveted armor (Cheapest armor)
  
• Gasoline Engine (gives extra speed)
  
• Engine: 8 points
  
• Armor: 14 points

Design explanation:

The goal of the TD is simple; maximize piercing and maximize armor. The division's overall piercing and armor is determined both the average of ALL battalions, but also the batallion with the highest piercing and armor.


Medium Flame Tank (1939)


The flame tank is unlocked by researching the Engineers II technology.
This flame tank is designed to as cheap as possible, since its stats gets massively reduced (%) being a support flame tank. For Flame Tanks, all combat stats get reduced, which means you can add on Dozer Blade and Fuel Drums. The 1938 hull is used since it's cheaper. The speed of this flame tank was increased to 8 km/h to match mechanized equipment.

Mechanized (1940)


Redesign to cut the cost of mechanized equipment in half! This will cost 100 xp in total.

Land Cruiser (1942)

Note these stats are bugged, and are lower in reality.

The land cruiser has fantastic stats, but bad terrain modifiers, and extremely high resource cost (However, production cost is extremely low; you only need 1 per batallion!). Best used in defensive positions, as a mobile bunker. Can also be used for attacking, however.

Medium Amphibious Tank (1941)


Medium Amphibious Tanks have better terrain stats than normal Medium Tanks at naval landings, rivers and marches; terrain types normally difficult for tanks to cross. This means that amphibious are objectively better than normal medium tanks.
However, they are unlocked very late in the game (1941), so typically you can't use them. Also, Amphibious drive costs lots of research time to unlock.
Still, these Amphibious tanks are very strong; combined with Amtracs, they will give you virtually no river/marsh/naval invasion penalties.

Games typically don't last much longer beyond 1943, but when you do go into the real late-game, keep on upgrading your tanks!

Design tips:

• The mothership aircraft (special project) has amazing stats and huge range, but very high resource costs. Only build these if you need the range!
  
• Depending on where air combat will take place, make sure your plane has enough range. In Europe, you'll want a minimum range of 600 km. Outside of Europe, a range of 900 km or more is recommended.
  
• Try to use as much of the weight limit as possible. For fighters, light/heavy machine guns have a good weight/damage ratio. For CAS, bomb locks have the best weight/damage ratio, and also the best damage/IC ratio.
  
• You should upgrade the modules whenever possible. Make modifications where needed; e.g. 'strategic materials' can be useful if you lack aluminum.
  
• The 1940 Airframes, 1940 Engines and 1940 Torpedoes are extremely strong. You should try to rush those technologies. The 'Industry Liasons' Spirit should be used for increased research speed!
  
• Various countries have focuses that grant research bonuses for e.g. CAS planes. These apply on the small airframe, since the small airframe is used as CAS. This way, it is possible to have a 1940 plane at the start of 1939!

Weapons:

• 4x Light Machine Gun (upgrade to Heavy when possible)
  
• 4x Light Machine Gun

Modules:

• 1x Engine II
  
• Drop Tanks
  
• Self-sealing Fuel Tank (or Armor Plates)

Design explanation:
Try to obtain the 1940 fighter asap: it is much, much stronger the 1936 design. The MG is cheap, has good damage and doesn't reduce agility. Self-sealing and armor plates add air defense. Note that the short range can be a problem outside of Europe. In Europe, the range is large enough.



Weapons:

• 4x Heavy Machine Gun
  
• 4x Heavy Machine Gun
  
• 4x Light Machine Gun
  

Modules:

• 1x Engine III
  
• Drop Tanks
  
• Self-sealing Fuel Tank (or Armor Plates, if you have little rubber)
  
• Armor Plates (or add a range module)

Design explanation:
Updated for the TOA update!
A proven design; LMG and HMG are the most cost-efficient weapons that give air attack. Self-sealing and armor plates add air defense. Note that the range can be a problem outside of Europe, so add extra range modules if needed. In Europe, the range is large enough.



This plane can be unlocked via a special project. These planes are very resource-intensive, but have huge range and great stats (better than 1940 fighters per IC). Build these if you need fighters with huge range.



Note: The bomb locks has the highest CAS damage per weight of all modules, and is more most cost-effective than the small bomb bay. Heavy bomb locks (1940 tech) have the highest damage per IC.
For CAS in 1936, the small airframe is used. Though it lacks the range of the medium airframe (and damage in a land battle), it has some key advantages. Firstly, the damage/IC ratio is better for small airframes. Secondly, any type of CAS is equally likely to be shot down by divisional AA, which makes cheap planes superior to expensive aircraft.



Weapons:

• Bomb Locks
  
• Bomb Locks
  
• Small Bomb Bay

Modules:

• 1x Engine III
  
• Dive Breaks
  
• Drop Tanks
  
• Self-sealing Fuel Tanks, or more range

Design explanation:
This design uses 3x bomb locks, due to the weight limit on the plane. Dive breaks increase survivability, and drop tanks give the plane the extra range. Since you will lose always be losing CAS to divisional AA, using expensive medium airframes is not recommended.



Important: Put half on Naval Patrol, the other half on Naval Strike for maximum effectiveness!

Weapons:

• 1x Medium Torpedo Mountings
  
• (optional) 1x Recon Camera

Modules:

• 1x Engine III
  
• Drop Tanks
  
• Extra Fuel Tanks
  
• Floats

Link to Navy Guide here!

Design Explanation:
This plane can perform Naval Patrol, Naval Strike and Port Strike. Put half on patrol, half on strike for maximum effectiveness. Floats add addtional ship detection. A recon camera was added such that when the sea battles are won, these planes can be used for recon duties on land. The 1940 Torpedo technology is very important: the damage output of the 1936 Torpedo (multiplying Naval Targeting and Naval Attack) is 2.5x higher than the 1936 Torpedo! A similar design can be used for carrier Naval Bombers.

Disclaimer: the stats are distorted due to the console command ''research all' used to create this. This templates can be used throughout your game.

With the release of AAT, the 'ideal' combat width has become lower than before, due to terrain CW changes. On Reddit, people talk about what they think is best, but in reality, anything between 10-35 CW can work currently. I will use a smaller CW for infantry, and a wider CW for tanks, which is very common in all guides. See the theory section on CW for more the reasoning behind this.

Special forces will be added later. Still, remember that tanks are better at attacking than special forces.

Infantry (1936)


Battallions:

• 8x Infantry
  
• 1x Artillery

Support Companies:

• Engineers
  
• Artillery
  
• Anti-Air
  
• Rocket Artillery (optional, after 1940)

Most of your army will consist of infantry, which will defend the front line. Infantry is good at defense, but poor at offense.

Good combat widths for infantry are anywhere between 19 CW and 30 CW;
Larger combat width divisions have less org per combat width, but will be more cost-effective in terms of damage dealt per IC, due to engineers giving a %-bonus on various terrain types. Anything in the 10-30 range will work in your games.

Armored Infantry (1936)


Battallions:

• 8x Infantry
  
• 1x Artillery
  
• 1x Medium Tank (as cheap as possible, only maximize armor)

Support Companies:

• Engineers
  
• Artillery
  
• Anti-Air
  
• Rocket Artillery (optional, after 1940)

By incorporating just 1 tank into your standard Infantry division, it gains enough armor to not be pierced by regular infantry. Anti-air tanks require fewer units than standard tanks, so AA tanks are used. Very cost-effective. Good in Single Player, but in Multiplayer opponents can simply add Anti-Tank to counter this division.
Support companies: Artillery, Anti-Air, Engineers

Coast Guard (1936)


Battallions:

• 5x Infantry

Support Companies:

• Artillery
  
• Rocket Artillery (optional, after 1940)

This division's main purpose is to hold their position as long as possible against enemy invasions. Note: this can also be used as standard infantry, if you don't have enough production capacity for proper infantry. A division width of 10 is chosen, since this is the smallest width at which the stacking penalty is 0%. Enemies will have a tough time breaking through all the ORG this division offers (creating an ORG wall), giving you time to bring in reinforcements to repel the invasion. Put these on the ports, and the coastal tiles directly adjacent to them. Real infantry is better, but this is much cheaper, allowing you to cover a larger area. After fully covering your ports, upgrade these into real infantry.


TLDR: Use Cavalry as garrison. MP becomes IC-efficient with 5 Cavalry or more.

Cavalry is more efficient at suppression than infantry manpower-wise, and in addition slightly more cost-effective IC-wise (3 VS 3.3 IC per suppression). The combat width of this division does not matter. If you have a pure cavalry division empty of support companies, use that one. Else, create a new division, and put 1 cavalry in it as shown below. To do this, open any division via 'edit', click the arrow, then 'create empty'. This way, this division will only cost 5 army XP.
The theoretically best design is 1 Military Police (MP) support company with 25 light tanks: these have lower manpower requirement per suppression point and take fewer casualties. Any light tank works, so bulid the cheapest design possible.
However, your army XP and IC is better spent on other things first! This design is in practice never worth it; if you have the IC for building light tanks, you typically also have enough manpower for cavalry.


Battallions:

• 1x Cavalry

Support Companies:

• None

A garrison division that costs only 5 army xp, use this in most of your games.


Battallions:

• 25x Cavalry

Support Companies:

• Military Police

This garrison is the most cost-effective, giving +40% suppression (1939) due to MP. From 5 divisions onwards, MP becomes worth adding in terms of cost-effectiveness. Only upgrade your garrison division after finishing your doctrines! Try to choose an occupation law, such that resistance is at 25% or lower to prevent any debuffs. At the minimum aim at under 50% resistance. Using harsh occupation laws will reduce your compliance gain, and will require a much larger garrison. So use those with caution, if you wish to occupy the land long-term.


Change garrison division here.

Only start building tanks once you have achieved air superiority! (note: aircraft designer picture here is outdated)

This sections shows which divisions should be used for attacking. Breakthrough is a very important stat for attacking; the only battalion type granting significant breakthrough is the tank. Marines, Mountaineers and motorized also have slightly increased breakthrough compared to standard infantry; they are better than infantry, but still worse than tanks at attacking. Other important stats for offensive divisions are armor (for increasing damage output and reducing damage taken) and speed (for encirclements). Always set these divisions at 'elite' reinforcement priority.

The ratio between tanks and motorized/mechanized infantry depends on your ORG (keep it above 30). The tank/infantry ratio is typically around 50/50; with mobile warfare, you can use a 60/40 ratio.

The highest combat width with acceptable combat efficiency in AAT is 35 CW; don't make your divisions larger than this number!

Always include:

• Medium Flame Tanks for the attack bonus on many terrain types,
  
• Assault engineers for various attack bonuses.
  
• Anti-Air to reduce CAS damage taken by 66%.
  
• (Helicopter) Logistics Company reduces supply usage and fuel usage. Quite important, as newly-conquered land does typically not have much supply. Replace by helicopter Logistics once researched.
  
• (Helicopter) Motorized Recon company. Recon companies give movement speed bonuses, allowing for encirclements. Recon will also provides reconnaissance.

Medium tanks (1940)


Battallions:

• 8x Medium Tanks
  
• 8x Mechanized/Motorized
  
• 1x Medium Tank Destroyer

Support Companies:

• Assault Engineer Company
  
• Medium Flame Tank
  
• Anti-Air
  
• Logistics (replace by helicopters)
  
• Armored Recon Company (replace by helicopters)

If you haven't unlocked mechanized yet, use motorized infantry until you can replace them by mechanized.
A mix of tanks and motorized/mechanized is important to ensure you division has enough ORG and HP. This template can also be used for Light/Heavy/Amphibious tanks, as it is the ratio between tanks and infantry-like units that matters for obtaining the necessary ORG/HP.
One Tank Destroyer is included to obtain piercing. To get more hard attack, some medium tanks can be replaced by medium TDs, trading breakthrough for hard attack.
Any combat width of 35 or lower will work for tanks. As can be seen in the CW section, 35 is the ideal CW for Russia and North Africa. Since that number can't be reached by combining 2 width divisions, we use 34 instead.

Medium tanks with Helicopter (1940)


Battallions:

• 8x Medium Tanks
  
• 8x Mechanized/Motorized
  
• 1x Medium Tank Destroyer

Support Companies:

• Assault Engineer Company
  
• Medium Flame Tank
  
• Anti-Air
  
• Helictoper Logistics
  
• Helicopter Recon Company

Identical as the standard tank division, but we now use helicopters instead.

Space Marines / Space Mountaineers (1936)


Battallions:

• 8x Marines/Mountaineers
  
• 1x Artillery
  
• 1x Medium Tank (maximize armor and breakthrough)

Support Companies:

• Pioneers
  
• Artillery
  
• Anti-Air
  
• Rangers
  
• Medium Flame Tank

These are your budget elite forces. Very good at operating in difficult terrain, and much cheaper than tank divisions. If you don't (yet) have enough resources for tank divisions, these will be a very good option. The tank is included to add lots of breakthrough and armor to the division.

Support companies: Anti-Air, Artillery, Rangers, Pioneers, Rangers

Land Cruiser Division (1942)

Note: Division values are bugged here.

The Land Cruiser has extremely good stats, but has hefty terrain penalties. To abuse both of these properties, a good strategy is to use this design with a low-combat width division, such that we achieve extremely high Soft Attack per combat width. We stack as many terrain modifiers as possible, to offset negative modifiers from the Land Cruiser.

For infantry, you can use:

• Mountaineers - good for attacking mountains/hills
  
• Marines - good for attacking over rivers.
  
• Amtracs - good for attacking over rivers, high hardness and high HP.

MIOs give various bonuses, the structure of an MIO tree depends on the country. Therefore, I've simply listed the best modifiers to take.



For fighter aircraft, it is important to keep a balance between attack, defense, agility and speed. Since fighters have the largest impact on the game of all aircraft types, focus on improving your light aircraft designer. From the wiki[hoi4.paradoxwikis.com], you can see the full formula for calculating losses and damage.
I will use a 'multiplication factor' to indicate how effective a 1% increase in its respective stat is to overall combat effectiveness, assuming enemy aircraft are similar in stats to yours.

Mathematical details:
When choosing between 5% extra agility and 4% production cap, the 5% extra production cap is better. Simply multiply the 'multiplication factor' with the stat increase. Since 0.05*0.65 = 3.3% (agility), whereas 0.04*1.25 = 5% (produciton cap).
TLDR; high multiplication factor = good.



1. Production efficiency cap. Multiplication factor of 1.25 (assuming a base production efficiency of 80%, in the year 1939).
2. Production cost/ production output. This carries a multiplication factor of 1. Having more planes than the enemy grants air superiority (to support ground troops), and additional air detection (which allows you to engage additional enemies), which makes it better than air attack.
3. Production efficiency gain. This carries a multiplication factor of 1. Strictly worse than production efficiency cap, but will still increase production, especially when production efficiency isn't capped out.
2. Air Attack. This carries a multiplication factor of 1. Air attack is slightly better than defense, as you will shoot down more enemy support planes as well.
3. Air Defense. This carries a multiplication factor of 1.
4. Agility. This carries a multiplication factor of 0.65.
5. Speed. This carries a multiplication factor of 0.45. (and a tiny bonus from absolute speed, which is negligible)
6. Reliability. This stat is not that important, as only a small fraction of losses are caused by reliability losses. However, this reliability is quite important in high-attrition environments, such as snow/sand storms.



For tanks, the story is much simpler. You'll almost always want to mass-produce medium tanks; quantity over quality. Go for cost-reducing/production first, then soft/hard attack, then speed/reliability/breakthrough.

As for policies, focus on increasing the tank production as much as possible.

Important: Pick your spirits first, then your doctrines.
Extra information is found in this video.


TLDR; go Superior Firepower when in doubt.

- Mobile warfare doctrine: This doctrine is good if you're going for tanks and motorized infantry. It gives tons of ORG and breakthrough to your tank divisions; having high ORG per (motorized) infantry means you can increase the tank/infantry ratio in your divisions, which results in more damage! Especially the first picks are quite strong, for a strong army at the beginning of the war. Note that the doctrine is defensively quite weak. Take the right branch, then the right branch. The first right branch gives access to the tactic 'breakthrough', by far the best tactic in the game! On the other hand, first left branch however gives even more ORG to infantry, allowing you to use even an even higher tank/infantry ratio.

- Superior Firepower doctrine: The most versatile and easiest doctrine, as it is great at both defense and offense; it always works. This doctrine simply gives lots of stats, especially handy for single player. Take the right side, then the right side.

- Grand Battleplan doctrine: This tree a bit stronger than superior firepower, but requires careful gameplay. The first icon of this tree is extremely strong defensively; +10 entrenchment results in +20% stats when defending, which is when combined with %-entrenchment modifiers very strong. It also gives very good planning bonuses; using the planning bonus fully, it's stronger than any other doctrine! If you decide to use this doctrine, go down the right side.

- Mass Assault Doctrine: The first few icons are relatively weak compared to the other doctrines. However, when finished, this doctrine is very strong offensively when taking the left tree. This doctrine can be used for the right side, to achieve an extremely high reinforce rate (right side), allowing you to keep on reinforcing a province that is in a losing battle. However, the left side, once finished, is a very strong doctrine for tank divisions.



- Strategic bombing: Provides large bonuses to strategic bombing, crippling enemy industry. Almost as good as operational integrity at shooting down enemy fighters.
- Battlefield support is arguably the best doctrine in single player due to the large bonuses it gives to CAS damage.
- Operational Integrity: Grants various bonuses to various air missions. Grants stats like agility and air detection, improving the K/D of your fighters. The best doctrine for shooting down enemy fighters.


The best spirit for every category is indicated in red; multiple are ranked when limited by ideology or doctrine.

Spirit of the Academy

• Bold Attack

Spirit of the Army

• Relief of command (Democratic),
  
• Motorization drive (Mobile Warfare)
  
• Overwhelming firepower (Overwhelming Firepower)
  
• Quick improvisation. Don't forget to use commander abilities!
  
• Professional Officer Corps, earns itself back after 350 army XP.
  
• Situational (if you need lots of PP): State Serves the Military (Fascist)

Spirit of Division Command

• Logistical Focus (Grand Battleplan)
  
• Maneuver Warfare (Mobile Warfare)
  
• Operational Reserves (Mass Assault)
  
• Smoke and Fire (Superior Firepower)

Bold Attack or Meticulous Preparation?
Bold attack is most of the time better than Meticulous Preparation since attack has an effect in high-supply areas, whereas logistics does not. Both give similar stats in damage output: Attack -> 2.5% attack increase. Logistics -> 2.56% extra in soldiers on frontline available (=2.56 extra attack available) -> Logistics gives the same damage output as attack. However, Logistics also gives extra ORG to frontline battalions, which makes it better in low-supply areas.

Air Spirits

The best spirit for every category is indicated in red.

Spirit of the Airforce

• Air Crew Surveys

Spirit of the Airforce Command

• Centralized Control

Tactics

More information in this video.
Preffered tactics can be assigned to both generals and on a country-wide level, giving you higher chances of picking a specific tactic.
Best offensive tactics (in order): Breakthrough, Suppressive barrage, Blitz.
Best defensive tactics (in order): Backhand Blow, Elastic Defense, Overwhelming Fire.

Change the preferred tactic by clicking the icon next to the doctrine.

For many more beginner tips, I strongly recommend the Pydgin YouTube channel.
For more advanced strategies, check out the 71Cloak Youtube channel.

• Shift-click on the 'exercise' button to let your troops train until they reach their maximum exercise level.
  
• You can also shift-click aircraft to train them; this is extremely important for fighter planes!
  
• Holding shift allows you to draw a smooth frontline for a field marshal, which prevents gaps from being created.
  
• 1 Anti-air decreases damage from CAS by 66%, so Anti-air is quite strong.
  
• More than 1 AA division will not decrease damage taken further, but it will inflict additional losses on enemy CAS.
  
• Given enough air support, basic infantry can sometimes push through enemy lines.
  
• Flame tanks, support equipment, anti-air, anti-tank and tank destroyers are vulnerable to attrition due to their low quantities in divisions, so put extra factories on them to prevent shortages.
  
• Set all field marshals to 'supply by truck' (3 trucks icon): this increases the supply range of supply hubs dramatically for all units under that field marshal. Use transport planes to supply your troops advancing into enemy territory: railroads require quite some time to repair themselves.
  
• When in a stalemate, but you have superiority in the air, logistics strike will cripple enemy supply.
  
• Railway guns decrease enemy attack, defense and entrenchment. Though expensive, they can be well-worth the cost. Always assign a railway gun to your tank divisions!
  
• Creating a variant of mechanized equipment can reduce its cost from 8 to 4 IC, halving its cost.
  
• Send an attaché to countries that are at war to receive 10% War Support, and 20% of their army xp gain.
  
• Use a Tank/Plane Designer Company to give your tank/plane extra stats.
  
• Always use dispersed industry, as this heavily outproduces concentrated industry for a typical game. Source.

Thank you for taking your time to read this guide. If you have any questions or suggestions, do not hesitate to contact me!

Q: Will 19W work against (20W, 40W, Tanks, etc.)?
A: Since the Barbarossa update came out, targeting by divisions was changed, and combat width per terrain type was changed too. 40W have too little ORG (per combat width); do not build 40W divisions!

Q: I can't design tanks, why is that?

A: You need the Barbarossa DLC to use the tank designer.

Q: I'm playing a small country, what do I produce?

A: Focus on producing guns and artillery. Use e.g. the 19W Infantry Template. Add Engineers last (or skip them), since these are the most expensive and least bang for your buck.

Q: When do I stop building Civilian Factories and start building Military Factories for the highest total factory output?

A: This is different for every country; for e.g. Germany, it's best to start building Mils already in January 1938. As a rough rule of thumb: Around 2 years before war breaks out. Of course, the timing depends heavily on your situation!

Q: Planes from 1940 onwards perform much better than earlier designs; should I only build planes after I've unlocked the 1940 tech?

A: Even though Fighters and CAS are much worse before 1940 tech, you should still produce earlier designs; having bad planes is better than having no planes!

For this guide, I have created a combat width simulator.
This simulator includes the overstack penalty.

You can copy-paste the code into an (online) compiler directly.
Source: https://github.com/Vezachs/hoi4-combat-guide/blob/main/combatwidth.py
Examples of online compilers you can use:
https://trinket.io/embed/python3/a5bd54189b
https://www.codabrainy.com/en/python-compiler/
https://trinket.io/features/python3

List of terrain types (excel document): https://forum.paradoxplaza.com/forum/threads/hoi4v-1-10-8-province-summary-spreadsheet.1496152/