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Chapter 3
Supply and Attrition

So you've built the largest army the world has ever seen - it's time to march it into the heart of enemy territory and bring them to their knees, right?

Ah...no. Your army, selfishly, has a foolish obsession with eating, not dying of malaria and tropical disease in the tropics, not leaving their parched bones in the desert, and not turning into a popsicle in Siberia. This is modeled by attrition. Not only is your army extremely selfish about their self-preservation, but your populace is also selfish about wanting their family members to come home alive! Every time your men die of attrition or battle, you will take some war exhaustion (explained fully later - for now, understand that war exhaustion alone can cripple a nation).

In the time period, army supply was not a simple prospect, and more than one nation found their armies winning battles only to lose the war due to supply issues or the weather (ask Napoleon how that invasion of Russia went...). The same thing applies to your army.

Every province has a supply limit, which is how many men can be in the province before they start taking attrition. Attrition is a catch-all statistic, that covers desertion, starvation, and death from the elements, and it can easily do as much or more damage to your armies as the enemy if you're not careful.

Since we still have Prussia loaded in 1789, go ahead and click on the Brandenburg province (your capital). Mouse over the word "Supply Limit" shown below.

ct3supplymouse.png


Here we see that Brandenburg has a base supply limit of 6.0, which is then modified by 5x (since you own it), and 3.33x (from technology), for a final value of 100.

If you click on a Meissen (a province south of Brandenburg, owned by Saxony), you'll see the supply limit is 10! Mousing over it shows that the base is 3, and then you get your technology bonus of 3.33, leaving you with the supply limit of 10. The sharp difference is because Meissen is not owned, and you do not have military access.

The supply limit calculation is available at the wiki, but the key drivers are base tax, fort level, province status (owned, allied/military access), occupied, enemy, etc) and technology.

Always be aware of supply limits, because those determine how many troops you can keep in a province without suffering attrition. This doesn't mean you can't go invading the enemy, but be aware that you will take attrition if you just wander around their territory!

As for attrition, it's important to understand when attrition is calculated:
* Attrition is calculated for every army on the first of the month.
* Attrition is instantly calculated whenever an army enters a new province.
* Attrition is ignored if the army is in battle (including when you enter a province to fight!).

Thus, if you can attack an enemy on a plain, the attacker will have an advantage - no terrain penalties, and no attrition penalty for movement!

There are several ways you can achieve your goals without wiping your regiments and manpower pool out with attrition:

1.) Use a large stack of infantry to assault and occupy key points in enemy territory. Occupied territory gives increased reinforcement and supply limit, compared to surrounding enemy provinces.

2.) Try to get military access with your enemy's neighbors - this will give you more options to gather troops in provinces with higher supply limits and reinforcement rates before you actually start battle.

3.) Beware weather and other attrition modifiers! Tropical provinces increase attrition (and reduce supply limit - though the tooltip won't tell you!), as do desert provinces in the summer, and some provinces in winter. You can tell when winter has arrived by checking the Max Attrition tooltip - attrition modifiers increase attrition and decrease supply limit by the same amount. Looted provinces (ones that have had an enemy army come through recently) increase attrition, as do provinces where the owner has scorched the earth (the AI doesn't do this - thankfully).

4.) Keep armies split up into smaller groups so that they don't go over the supply limit - even at home. At lower tech levels, your supply limit is much lower (since you can't build high level forts and don't get huge technology bonuses), and it's very easy to accidentally leave an army in a low-limit province.

5.) Check the outliner! Your army's strength will be red if attrition is greater than the reinforce rate.

6.) Check the War Exhaustion counter (explained later) on the Coat of Arms Land and Naval screen. If the tooltip says you're taking attrition and you're at peace, chances are you left an army somewhere that it's taking attrition. Don't waste unnecessary manpower this way. Your army's attrition can be viewed by selecting the army, and looking at the % under the # of men. Mousing over it will show you your unit weight, supply limit, and reinforcement information.

ct3attritionmouse.png


7.) Attrition is calculated based on the total number of men, not the number of regiments. If you've pulled regiments home to reinforce, make sure that your province can handle the army's size when fully reinforced, otherwise, you'll immediately take attrition. Also, beware that the supply limit shown is rounded - assume it's 1 less than the stated amount.

8.) Attrition is calculated before reinforcement. This is a double edged sword: if your army is in a province where it can reinforce fully, you'll still be at full strength, but it's also easy to have an army taking attrition and you don't realize it.

Finally, attrition is a double edged sword! Use it against the enemy by Scorching the Earth, especially in provinces that suffer from additional attrition modifiers. In the above screenshot, "Scorch the Land" can be seen in the lower left corner. During a war, you can scorch a province that you own and control, which will then causes several harsh modifiers:
-20% population growth
+10 max attrition
-75% tax income
-1 supply limit

Scorching a northern Russian province in January can make for a devastating tactic - as your enemy can take up to 30% attrition monthly! (5 normal + 10 for Severe Winter + 10 from scorched earth + 5 from Looted!)

The AI will either try and brute strength its way through the province (after taking huge losses) or will try to avoid the province if it can. This can buy you time and space to hold them off, or force them to take large losses moving troops through the area. On the flip side, the province is nearly worthless for taxes, and will cause you attrition when you come to retake it!

--- Trick: If a war breaks out and you have no armies in the area, see if you can hire a mercenary in the province and have them finish before the enemy's army gets there. Slow the game down, and the day or two before the enemy arrives, scorch the earth and disband the mercenary. ---
 
Don't blame the weather, it is not that cold in Moscowy in the game. Blame the weak supply lines, harassing of supply-trains, and a freaking huge doomstack with Stygian attrition. :p
 
Chapter 4
Manpower and Reinforcement

Armies are made up of men, and no nation can call upon an infinite number of warm bodies to press into military service. To model a nation's ability to raise and maintain an army, the game tracks your nation's manpower.

Manpower is calculated on a province level, then added up to provide your national manpower. Manpower is first calculated into a base manpower (see the calculation at the wiki here), and then modified by various province and national modifiers.

Click on Brandenburg, and mouse over Manpower.

ct4mpmouse.png


Brandenburg has a base manpower of 3744, which is then modified by being the capital, in the national focus area, the Land/Naval and Quality/Quantity slider, the National Conscripts NI, the HRE Imperial Integrity modifier (based on # of states left in the empire), and a Grain Depot in Neumark.

(in the above screenshot, I've built a Grain Depot in Neumark to illustrate manpower modifiers).

Each province's manpower is added up and doubled to create your National Manpower pool. That manpower represents 2 years worth of manpower, so you will replenish 1/24th of your manpower pool monthly.

Your manpower pool is used to train new regiments, and to reinforce existing ones, thus, allowing your manpower pool to run out will cripple your ability to continue waging war.

Reinforcement is done by army, and the maximum reinforcement rate is based on the status of the province that the army is standing in, multiplied by the %age of maintenance paid (slider all left = 0% reinforcement, slider all right = 100% reinforcement):
Code:
Owned:				200 men/regiment/month
Occupied:			100 men/regiment/month
Borders owned or occupied:  	50 men/regiment/month
Else:				20 men/regiment/month

Furthermore, armies will reinforce based on the order they appear on the Outliner (important if you run out of manpower). If you absolutely have to prioritize an army for reinforcement, open all armies above it on the outliner, create a new army in the same province, and move all regiments to the new army. That will move the new army to the bottom of the outliner.

Tips:
1.) A regiment's strength is based on the number of men that are in that regiment, thus, 10 regiments of 500 men is weaker than 5 regiments of 1000 men. One tactic is to consolidate regiments one by one, so that you keep the same number of regiments, but they are shifted so that one has 1000 men, and one has the remainder. Then, move the remainder home to reinforce at the maximum rate.

To consolidate armies, put each regiment you want to consolidate in their own army, then click the Consolidate Regiments button. --- The consolidate regiments button will put 1000 men in each regiment it can, the remainder in the last regiment. If you don't have enough men for all existing regiments, the remaining regiments are lost (ex: if you have 4500 men in 10 regiments and consolidate them all, you'll have 4 regiments of 1000, 1 regiment of 500, and the other 5 are gone for good). Don't consolidate large armies all at once if you don't have to! ---

To consolidate regiments:
a.) Pick your army. Click on the Split Army button (see arrow)

ct4cons1.png


b.) Move the regiments you want to consolidate into a new army. Click Close.

ct4cons2.png


c.) Minimize your main army (- button at top right of army view), and click the Consolidate Regiments button (see arrow).

ct4cons3.png


d.) Your armies are now consolidated! Repeat this process to have one army of full strength regiments and one of understrength ones to go home and reinforce.

ct4cons4.png


2.) As noted in the last chapter - assaulting and occupying a path into enemy territory will provide a base where reinforcement is much faster than it would be in an unoccupied enemy territory.

3.) The National Conscripts NI is useful for nations that are small, in multiplayer (where players grind through their manpower pool quickly), or for nations that consistently have to fight and can't recharge their manpower pool (such as tribal nations). Don't be afraid to take it.

4.) Once you get Government Tech 8, you can establish a Grain Depots in grain provinces in your National Focus (it costs 5 magistrates). A grain depot gives +5% national manpower and +10% force limits (at the cost of -50% trade value in the province, not so bad for a grain province with low prices anyway). You can only build one, so sticking it in your poorest province (or better yet, an overseas one!) is best.

5.) Regimental Camps (Land 17) are also useful on a province by province basis.

6.) Manpower is severely limited for overseas provinces, since there is a 50% penalty, and a maximum of 1 unit for overseas provinces. Provinces in the Americas have crap base manpower anyway, thus, a large colonial empire is not particularly helpful in the manpower department. If you ever get an event with a choice that increases manpower in an overseas province, it's not worth it.

7.) A Center of Trade will drastically increase province manpower, giving a +10% manpower boost per trade level (100 ducats). Placing a center of trade in a high manpower province with the same culture will give you a noticable manpower boost.

8.) Finally, --- always check your manpower before declaring war! ---. Declaring war only to find out you can't reinforce will make you feel really dumb, especially if a major power steamrolls their way through your non-reinforcable army.
 
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Why would one ever consolidate armies?
Whatfor?

If you want your main army fighting at full strength and can't afford to stop and reinforce, you can consolidate a couple of regiments at a time to split them up - full strength armies to fight, the dregs to go home and reinforce while your main army is fighting. A few months later, the reinforced regiments return to the main force, and you can repeat the process if necessary.
 
I still don't see micromanaging your armies that way is really necessary, it is just about a few hundred men more or less?

Let's say, for simplicity, you have 1100 men in enemy territory, in two regiments with 550 in each. You consolidate them, so you now have one with 1000 men (which will fight better than two with 550) and another with 100. Then you send the 100-man regiment to a controlled province where it will reinforce more quickly. You can then rotate the first one out if it's taken damage.

Obviously this is more effective with larger armies, but it still applies in this example: you are stronger, reinforcing faster, and more flexible all at once.

It is a bit of micromanaging, and not strictly necessary, but if you are in a tight spot, and the war is in the balance, this could give you the edge.

Did I sum it up right, Naggy?
 
I've never used scorched earth because of the nasty modifiers. Plus, it seems like to be effective (except in the hiring/firing mercs strategy you gave, good idea), you'd need to scorch several provinces, otherwise the enemy would just go around. I suppose it would be useful if there's a bottleneck. But I spend so much effort improving my provinces, all those negatives just hurt. I guess it's a mindset I need to get out of.

Is it really that useful? And, how long do the negative modifiers last?
 
Did I sum it up right, Naggy?

Exactly. Half strength regiments against full strength regiments are very very vulnerable.

Is it really that useful? And, how long do the negative modifiers last?

IIRC, looted and scorched earth last 1 year, but I'm not positive. Possibly 2 years. No more than that, I'm sure.

Against a larger opponent (France is the example players like to use, but Ming is a good one if you're playing in Asia), it can be the difference between life and death. Remember - you don't take attrition if you move into a province and immediately go to battle, so you can get a significant strength advantage, since attrition affects regiments easily. There are two likely scenarios:

1.) AI reaches scorched province, assaults, then moves on. In this case, you want to try and hit them between the assault and the end of the month - they took the initial attrition to enter the province, and their infantry has lowered morale.
2.) AI reaches scorched province, realizes they're hosed, try to go home. In this case, you want to try and nail them before they get home. One method is if you see them coming, slow the speed of the game down, and send your army so that it reaches the province after the enemy army arrives. Best case is if they arrive late in the month, and you arrive on the 2nd of the next month - they take 2 attrition hits, you get the month of reinforcement.
 
Chapter 5
Battles: Understanding Combat (basic)

(Of course, when I want to find a good example, the AI decides to not to send a giant army my way. Took me over a year to fight anything worth taking screen shots!)

Here is our basic battle:
Prussia has 6 cavalry, 12 infantry, and 2 artillery (Hereafter, we'll use c/i/a to designate army strength).
Venice + Austria's army is 5/4/1.

ct5battle.png


Whenever a battle is occurring, clicking on your army will bring up the battle screen, which will display the battle in progress. While you can watch the battle go on, you can't do anything except retreat.

The battle's tactical situation is simple: armies form up into lines, and hammer the snot out of each other. However, how they do so is where the real strategy of the game is played out.

Infantry, being the core of an army, defaults to being on the front rank, in the middle. Since they are on foot, they have a maneuver stat of 1 (they can attack the unit in front of, or immediately diagonal to, themselves.

Cavalry harasses units from the sides of the battle. Due to their speed, they have a maneuver stat of 2 (they can attack the unit in front of, diagonal to, or 2 slots on either side of, themselves.). This gives them exceptional utility when you outnumber an opponent - cavalry can crush the flanks of your opponent's army and collapse their line.

Artillery fires over the heads of the infantry by default. If the infantry leave the battle, or you have more artillery than infantry, they will be on the front line (which is very bad). Due to their range, they also have a maneuver stat of 2 (letting them hit units up to 2 squares away). Additionally, when they are behind an infantry unit, they do half damage (due to their range), but they give half their defensive pips to the infantry unit in front of them! Thus, a defensive infantry unit with an artillery unit behind it has a significant defensive advantage over anything coming at them.

The order of battle is then shaken up a bit:
* If an army arrives late to the battle, they start on the back row and on the sides. Thus, when armies arrive piecemeal to a battle, you'll end up with units out of their normal positions. Every day, the units will move closer to their correct position, but this takes time.
* When multiple nations fight in a battle on the same side, units from the same nation are generally kept together.
* If a unit retreats, the remaining units will move every day to close ranks, and again start trying to move to an "optimal" formation.

Enough about positioning, let's talk damage.

In the screenshot above, we see numbers flying up over our units head. My army (Prussia) took 177 casualties, and Austria/Venice took 1104! Why? This is the fire phase, and half their army is cavalry (essentially useless during fire and has lower defense), while I have their army outnumbered and can bring more death and destruction on them.

Let's break down how casualties are determined:

A battle has two 3 day phases: Fire and Shock. Dice are rolled both sides at the start of each phase, damage is calculated daily.

These rolls are then modified:
(Attack + Dice) - (Defense + Terrain) + (Leader Differential)

The modified roll is then multiplied by the phase tech level modifier (shown on the Land and Naval screen), discipline, regiment strength/1000 (so regiments that take casualties do less damage every day), and then by 6. The casualties are then reduced somewhat (I haven't figured it out, haven't seen anyone else figure it out either) by your military tactics rating if your army has the right composition (% based on tech, tactics rating based on your tech level). (the full formula is on the wiki but doesn't take tactics into effect)

The key thing to realize is that:
* Leaders solely add damage - they do not reduce it.
* The defending army will always get a damage reduction if there are terrain modifiers (hills, forest, rivers, mountains)

There are more wrinkles:
* Terrain modifiers are doubled against cavalry. Attacking with cavalry across a river into mountains is about as useful as attacking with cavemen.

* As a general rule, you get new infantry units more often than cavalry and artillery, and infantry generally has better base stats. The compensation is that they have worse modifiers. This means that the damage infantry does is less affected by the dice rolls (since they have a consistent advantage in the modified die roll, compensated by lower modifiers), and that infantry generally takes less damage (especially when supported by artillery!).

* Cavalry has comparatively low defense, is useful in the shock phase, and is heavily affected by die rolls. Using a lot of cavalry is literally feast or famine - if you get a string of bad die rolls, you can get wiped out.

* Morale damage is not affected by discipline or generals.

* Artillery dies when left alone. --- Never ever ever leave artillery units alone unless they're safe well behind enemy lines. ---

Add all this up, and here are some tips on creating armies that will do well in battle:
1.) Infantry is more versatile than cavalry - for Western European nations, it's often better to build a lot of cheaper (and at many tech levels, not much worse) infantry supported by 4 cavalry for the flanks. (4 cavalry is so that they'll sit on the flanks, hitting the enemy while the enemy generally won't hit them back. Muslim, Eastern, and Indian tech nations often have superior cavalry units, and they can use more cavalry and still stay under the % limit for military tactics.

2.) Once you hit Land Tech 23 (Chambered Demi Cannon), it's time to start adding artillery to your armies. Artillery is slower than other units, so before this, it's a waste except for sieges. For the optimal army, have 1 artillery unit per infantry unit.

3.) The AI always makes their ruler a general, and generally buys generals when they can. Furthermore, if you have Lucky Nations on, that adds +2 shock and fire to every general they create, giving the AI a large supply of decent generals. Unless you're squashing minor nations under your bootheels, hire a couple of generals when your military tradition gets high and keep them with your main armies.

4.) Because damage is based on your regiment's current strength, an army's ability to fight declines every day it's in battle, and is compromised until you've managed to reinforce back to full!

5.) Note that on the screen shot above, only 60 units can take part in a battle at a time for each side! Once you hit that limit, being outnumbered is meaningless, since you can't flank/be flanked.
 
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Mea culpa: Earlier, in Chapter 2, I said that discipline affects morale damage. It actually doesn't (I rechecked the calcs). The chapter has been updated.
 
Chapter 6
Battles: Understanding Combat (advanced)

Damage calculations:

Let's go under the covers, and see how a small part of a battle plays out.

First, we'll look at a case where an infantry unit is attacked by another infantry unit:

Prussia: Impulse Infantry (10/8 fire 8/7 shock 12/10 morale) - first number is offense, second is defense.
Austria: Impulse Infantry

Let's assume middle of the road: both sides roll 5. The modified die roll for the fire phase is:
(10 + 5) - (8 + 0) = 7 As you can see, because both sides are more offensive, both sides take a little more damage than the die roll would normally allow. The final damage would be then modified by the tech modifier (1.5) and discipline (124% for Prussia, 106% for Austria in the Rev France scenario, IIRC), and thus Prussia will do about 17% more damage than Austria solely due to discipline...

However, if we look at cavalry vs. infantry, we see a different story:

Prussia: Impulse Infantry (10/8 8/7 12/10)
Austria: Uhlan cavalry (5/5 7/6 8/8)

Fire phase
Infantry attack: (10 + 5) - (5 + 0) = 10
Cavalry attack: (5 + 5) - (8 + 0) = 2

Infantry has 5x the modified roll - worse, the tech modifiers in 1789 give infantry a fire modifier of 1.5, and cavalry only .5! The cavalry will end up doing around 1/15th the damage during fire...

Shock:
Infantry attack: (8 + 5) - (6 + 0) = 7
Cavalry attack: (7 + 5) - (7 + 0) = 5

Cavalry again has the lower modified roll, but the shock modifier in 1789 for cavalry is 4.5 to infantry's 1.5, giving them a decided advantage. Had cavalry gotten a roll of 9, they'd be doing a ridiculous amount of damage...

So let's look at infantry + artillery vs just infantry:

Prussia: Impulse Infantry (10/8 8/7 12/10) + Flying Battery (8/5 7/5 9/6)
Austria: Impulse Infantry

Shock:
Prussia: (8 + 5) - (7 + 0) = 6
Austria: (8 + 5) - (7 + 5/2 + 0) = 3.5

Austria loses over a third of their damage in shock...

Fire:
Prussia: (10 + 5) - (8 + 0) = 7 (from infantry) + (8 + 5) - (8 + 0) = 5 (artillery)
Austria: (10 + 5) - (8 + 5/2 + 0) = 4.5

Not only does Austria again lose about 1/3rd of their damage, but they take over twice as much damage since Artillery will do half their fire damage (with a modifier of 5.5, half is still a 2.75x modifier!)

--- Your biggest advantage over the AI is that the AI does not build optimum armies, nor will they pick the optimum advisors for what they are doing. ---

For a spreadsheet that will calculate damage for various unit combinations, look here. It does not cover the tactics modifier - I simply haven't had time to spend a few hours crunching numbers to reverse engineer it.

Terrain:

Terrain modifiers are huge, especially against cavalry. Whenever you can sucker an army into attacking you in hills, forests, or mountains, do so. Hills and forests give a -2 modifier, rivers and straits give a stackable -2 modifier (with other types), and mountains give a -4 modifier.

--- The AI will try and hunt down smaller armies and destroy them. You can occasionally sucker them by sending a small army to the province you want to fight in, and waiting for the AI to send their army in. Keep a smaller army in the next province (out of sight), and time it to arrive the day after the enemy arrives. ---

Fighting when you have lower tech:

As you can see, the tech modifiers are a large part of battle. If you are not Western European tech, you will slowly find that you cannot achieve parity with European powers (moreso if you are Muslim, Indian, or Chinese tech - if you are African or New World tech, you'll never have parity without westernizing!). Your only hope is human waves...since you'll have inferior units doing inferior damage.

Even within tech groups, tech level differences can be huge!

1.) Western Europeans do not get any new cavalry units until Land Tech 22. Starting around land tech 13, the Western European infantry units have enough raw pips to outmatch the two starting cavalry units.

2.) Being one set of units behind an opponent will put you at a consistent disadvantage every day in battle. If you can wait until you get the new unit before fighting a major power, do so.

3.) Use attrition against the enemy. If you whittle away 10-20% of their men before the battle starts, they'll be doing 10-20% less damage to your men and morale. If the AI thinks you are weak, you may get lucky and watch them lose a significant portion of their army assaulting their way through your lands, at which point you can wipe out their regiments.

Now, the most important part of a battle:

Outcomes:

There are two outcomes in a battle for the losing army:
* If the army runs out of morale after the first 10 days, they will retreat.
* If the army runs out of men before morale (possible as tech levels increase) or runs out of morale before the first 10 days are up, they will surrender.

As long as the army survives, all regiments in the army survive. If one guy staggers away from the battle in a 200 regiment army (this is an exaggeration, of course) and gets home, all 200 regiments will reinforce, and the enemy eventually can throw the whole thing back at you. Your goal, thus, is to wipe out enemy armies, forcing the opponent to pay to rebuild the regiments from scratch (slowly, since they'll now have war exhaustion).

To do this, you want to pursue the enemy army, so long as it doesn't run you smack into another huge enemy army (lest you just wipe yourself out).

There are three broad tactics here:

1.) Chase the enemy with a faster army (use a high maneuver general, or break off your artillery and have it follow separately, if the enemy has artillery). This lets you get to the retreat province first, and you will be the defender!
2.) Chase the enemy army with a larger, slower army. You won't be the defender, but the enemy army will take attrition when they arrive, and you won't. Usually, 2 is what happens.
3.) Start the battle somewhere that the enemy cannot retreat (no access, on an island, etc), which wipes the losing army. If the only way out is a strait, putting one ship across the strait blocks it, and forces the army back into battle (where it wipes out if there is 0 morale).

Conversely, you don't want your own armies wiped out:

1.) Try to never let your armies run out of morale and autoretreat. Your armies will pick some random direction, invariably somewhere that will get it killed.
2.) With the latest beta patch, you an choose a long retreat path. Your army will not reinforce until it reaches the end of the path, but it also cannot be attacked until it does.
3.) Optimally, cover your retreat path with another army.

Since the AI likes to concentrate their armies into one or two "doomstacks", wiping out a large enemy army can cripple their war effort, leaving their homeland ripe for the taking.
 
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At the end, I hope to make it a PDF. :)

Naggy, I'm making a document of this great AAR (and Rhadok's An Empire under the Sun) as it goes along and I can forward a copy of the PDF whenever you like. I do this both to help me comprehend what you have written and to have a paper copy to refer to.

Keep up the great work.
 
hmm i never found how to merge regiments before ...
thx for that

i'll add one thing : don't assault with all infantry armies , as a cheap mercenary newly created, retreating army , or rebel uprising will wipe you if the assault is failed