The major concept revolution implemented for HOI 3 is that every land unit has a frontal footprint, called a “combat width,” and every battlefield has a limited amount of frontage.  Only a certain number of units have room to be on the front lines. This is a serious step forward in combat realism.

Each provincial border typically has ten squares along its combat front. A flanking attack from a second province can cause the combat front of the province to increase in width, allowing more divisions to move to the front.

There are two ranks on any battlefield: Front and Reserve. There is only so much room on any battlefield, and once the space limit has been reached, the other divisions must wait in line for a chance to move forward. These become the reserves.

Here is a stacking penalty against each side for each brigade they have in either the front or the reserves. It becomes difficult to coordinate so many units, but effective Leadership can counteract that.

Land units have a variety of statistics and combat values:

• Strength – The number of soldiers assigned to the unit.
• Organisation – The unit’s ability to operate the way it’s supposed to.
• Effectiveness – The combination of all combat modifiers, including terrain or stacking penalties, etc., which is applied as a percentage of its strength effectively used in combat.
• Soft Attack – The unit’s capability against non-armoured targets.
• Hard Attack – The unit’s capability against armoured targets.
• Anti-Aircraft – The unit’s ability to shoot down attacking aircraft.
• Defensiveness – The unit’s ability to defend itself against attacking land units.
• Toughness – The unit’s ability to defend itself against defensive fire when it’s attacking enemy land units.
• Softness – The percentage of the unit’s strength which is “soft” instead of “hard” (armoured) in nature.

Each one-hour period of combat is played out in a series of “rounds” and a series of “shots” and “phases” per round. The shots occur during the Firing Phase, which is where damage to units is inflicted.  Units use their defensive values to “avoid” being hit.

Any division which has been successfully hit during the firing phase will take some damage. It is likely to suffer damage to organisation, and may also have damage to its strength. When a unit reaches zero organisation, it must withdraw from combat and begin retreating, even if it has significant strength left.

During each round of combat, each division is checked to see if it will “shatter.” Generally, if a unit has lost most of its strength or organisation and/or if it has a depleted officer corps, there is a chance it will shatter. Leadership, officers (the staff) and unit experience can help protect against shattering, but any unit will eventually reach its breaking point.

Divisions left in the reserve will not be able to fight unless they are advanced to the front lines later in the battle. When combat events, combat casualties, or other circumstances cause an open space of one or more squares to open up in the front, it allows a chance for a division in the reserve to move forward into that position and begin fighting.

Combat events can also happen during combat, helping one side or the other.  These are made more likely according to what skills or traits a unit’s commander has, and what combat doctrines its country has adopted. 

Air & Naval Combat

Air combat and naval combat are both handled much like they were in HOI 2, but with some significant improvements.  They each use a combat round system similar to what’s used for land combat. 

Air or naval units can be sent on patrols or set to intercept enemy units as they’re detected.  Either can also be sent on convoy raiding missions, and a variety of other types of assignments.  Ships in HOI 3 can be detailed to patrol a convoy route to fight off enemy raiders or submarines.

The addition of radar stations (which also represent signals-intelligence receiving stations) changes air and naval combat quite a bit, as well as having benefits for land combat and general intelligence.

Headquarters & Division Design

The unique headquarters system in HOI 3 allows you to assign divisions to corps, corps to armies, armies to groups, etc.  Each of these units may be controlled by a theatre command which is responsible for a certain region of combat.  Theatres or any lower level HQ may be turned over to the computer’s artificial intelligence (AI) so the player doesn’t have to move each division by himself.

Divisions are also modular in design.  You may use the new “Division Builder” to construct any of several types of “combat brigades,” such as motorised infantry or paratroops, and you can add “support brigades” like artillery or military police, which don’t fight on the front lines, but perform important combat support duties which add to the combat capabilities of the division.

Even after construction, you may combine different brigades into a division (up to a limit), or split them up into multiple units and even “mix & match” brigades in whatever combination you desire (again, within certain restrictions).