While short battles and operations with limited objectives is essential, a general understanding of how to fight an effective campaign can be instrumental in bringing down majors such as Germany or the Soviet Union.
Offensives on Large Fronts
Attacks of majors and, to a lesser extent, regional powers require moving multiple armies across a large front. In such campaigns, it is essential that corps, armies, and army groups advance along predetermined axes. If, say the US 3rd Army lands in Brittany and is charged with an advance through occupied northern France towards Caen, you wouldn't want one of its corps advancing through the French Riviera. The reason for this, other than the obvious organizational appeal, is that leadership traits and bonuses are only shared if the attached units are within radio range (200 km for Corps, 400 km for Armies, 600 km for Army Groups, and 2000 km for Theater HQs).
As mentioned in the Combat strategy section, there are several ways to advance along any front. However, there are a few more things that must be said with regards to a longer, more drawn out campaign. In strategic offensives, prudence must be at the forefront of any operation. It is better to use an unimaginative grinding approach than to risk an entire army in some grand encirclement. The payoff for such a maneuver is potentially great but the penalty is just as large. It also imperative that a continuous front be maintained and a mobile reserve kept just behind the lines so as to discourage any counterattacks. In HOI3, armored divisions and corps will slaughter regular front line infantry. Without some sort of reactive element in your offensive, a well placed counterattack can halt a seemingly inexorable advance and force you to re-allocate units from other parts of your front, thereby weakening other points in your lines
Defense along Large Fronts
There are several ways to defend against large scale offensives, perhaps the most intuitive is the trench warfare of WWI where all available units are placed on the front lines and ordered to dig in. While such a tactic is useful in infantry v infantry combat, armor will quickly break through and encircle any entrenched enemy. Perhaps the most viable defensive strategy in HOI3 is elastic defense or defense in depth. Here, reserves are placed behind the front lines to slow any breakthrough that occurs. If there are no reserves keep one or two divisions in battle as a rear guard and retreat the remainder to the next province. It is never a good idea to let the organization of your unit reach zero.
As defenders, it is your lot to pick the place where battles occur. A good commander will make good use of marshes, mountains, rivers and forests so that any attacker must do so with a significant penalty. Avoid fighting on plains where the attacker will not have to worry about terrain penalties. If done correctly, a good defender can make any enemy fight with a combat efficiency 20 to 40 percent below his own making battles more costly.
Organization and Morale
In any strategic campaign, morale (organization regain rate) and not the organization is the most important aspect of your units. The relationship between organization and morale can be best understood with a racing analogy. The organization of two units is akin to where two runners will begin a race. Their morale is the speed of the runners once the race starts. If runner A starts ahead of runner B but runner B is faster than runner A, Runner B will win any long distance race. The same is true for protracted offensives that lack superior morale.
Partisans and Revolts
Governments in Exile can build Resistance Cells that start spawning partisans or militia. Don't forget to regularly check the Revolt Risk map to see where revolts are likely (i.e. the map is red). You can reduce revolt risk by using collaboration government and by placing troops in the right location that have suppression abilities:
- 1.0 for Infantry, Cavalry and Armoured Cars
- 2.0 for Garrison
- 3.0 for SS and Military Police.
One of the main reasons to suppress revolts is to improve your supply situation. Units with high suppression that use up supplies in their province/supply route won't help. You also need units that don't use much fuel, can operate in difficult terrain, and can quickly move to put down revolts. The following table compares suppression values (on the left) with supply usage (across the top)
|1||AC||Inf, Guards, Imp. Guards||Cav||MECH|
All mobile units not mentioned (plus AA and AT units) have no suppression value. They affect the province they are in plus (to a lesser extent) the ones around it (up to two provinces away). To combat revolts, you can use paratroopers or station some cavalry behind your lines, ready to mop them up. The insurgents are militia units with 0 organisation, and very easy to beat, you only need weak units to beat them if you get them quickly. The main problem with revolts is if they occur on your supply lines - no supplies pass through rebel-held provinces. Supply throughput is also reduced merely by the risk of a revolt. In TFH, suppression was changed to allow it to affect annexed provinces.