3. Combined Arms Battle

Some nations use the term "All Arms" with this concept. The core of an Army is its Combat Arms – Infantry, Artillery, and Armor. The idea is about using multiple mutually supporting Combat Arms in a battle. This concept did not start in WWI when tanks were fielded on the battlefield. It goes back at least to the Thirty Years War (Gustavus Adolphus). Let's dissect things and look at the Combat Arms and their contributions on the battlefield.

One can view this as a triad consisting of an Arm with very high mobility, another with very high lethality, and another with very high survivability, with each of these characteristics compared to the others. This view has held up well over the ages.

3.1 Artillery

The US Army calls this the "King of Battle". That stems from the fact that artillery is the greatest producer of casualties, not just soldiers. It's armored vehicles, too. But that is not the main benefit of artillery. The large casualty production is the mechanism that affects one's enemy, and the execution of the enemy's plan matters.

While it can require a relatively large expenditure of ammunition and take considerable time to annihilate a unit employing artillery, the large number of immediate casualties inflicted on a unit with the initial rounds can degrade the target unit's effectiveness. In some cases, take it entirely out of the fight for a period ranging from minutes to days (requiring replacements to be assigned).

This impact is why artillery preps are fired at "likely" enemy positions just before an assault and why there is such a thing as a Final Protective Fire. The most important effect of artillery fire is to disrupt current enemy activities.

3.2 Infantry

The "Queen of Battle" is the name given to the infantry. The infantry's mission is to close with and destroy the enemy. It is the one Combat Arm that can seize, clear, and hold any terrain type.

There are several types of infantry units, mainly varying in mobility – leg (they walk), motorized/mechanized (moving about the battlefield in trucks, APCs, or IFVs), and airmobile (moving via helicopter). But when it comes to seizing and holding terrain, the infantry is the source of the phrase "boots on the ground".

Infantry is predominantly a close-range Arm, typically having its greatest combat power at ranges under 300 meters. Some infantry units have medium-strength anti-armor weapons, but generally, these range to around 1000m.

Infantry shines when deployed in complex terrain (those locations with a high Cover value) and often requires infantry or sustained intense artillery barrages to dislodge them from such areas.

3.3 Armor

The "Arm of Decision" has its roots in horse cavalry. Cavalry is the Combat Arm with the most significant mobility (across all subtypes within each), and it is that mobility that provides a Commander with the Arm's most considerable capability.

It's tempting not to equate the horse cavalry of old with tank units today, but that is mainly in error. The cavalry of the pre-WWI era had several battlefield missions – reconnaissance, envelopment, flank attacks, and security. One of the critical attributes of cavalry actions was the shock effect. Tanks certainly have a rich history of that.

In the WWII era and later, we see tank units having the most impact on combat operations when used as an exploitation force. During World War II, they were frequently used to conduct "break-in" attacks against prepared defenses. The results were mixed and looked to be mixed at best. Yes, tanks and break in. You do need enough tanks.

The most successful uses of armor seem to be to bypass, flank, or otherwise maneuver faster than the opponent can reposition to counter these actions.

Modern tanks (post-WWII) have a good combination of mobility, lethality, and protection. Still, they cannot function in all terrain (swamps, heavy forest, urban areas) and, unlike old horse cavalry, can't seize and clear terrain well (see Buford at Gettysburg on Day 1). Dismounted infantry in and amongst tanks can make a tanker lose sleep.

3.4 Support for Combined Arms

For Combined Arms to be effective on the battlefield, it has several types of supporting forces that provide various levels of force multipliers or critical service functions as described in the following sections.

3.4.1 Aircraft

There are several types of aircraft and helicopters that can perform reconnaissance and attacks on enemy forces. Scout helicopters to find enemy forces and attack helicopters that can deliver devastating Anti-Tank Guided Missiles (ATGMs), rockets, or cannon fire to wipe out enemy units. There are aircraft for Close Air Support (CAS) that fly in low and drop precision or unguided weapons on enemy units. Level Bombers that drop munitions from a higher altitude above most anti-aircraft gun systems. There are Suppression of Enemy Air Defense or SEAD aircraft outfitted with special anti-radiation missiles that home in on enemy air defense radars and weapon systems.

While helicopters are on the map and moved by the player to search and destroy the enemy, aircraft are allocated assets that sit some distance off-map and can be called in to carry out attacks as needed to support your ground battle.

3.4.2 Air Defense

Since the enemy will have aircraft to use against your forces, there is a need to have well-placed air defense assets to protect your troops. Air defense systems center around guns and missile systems in a wide array of platform types. These can be infantry with MANPADs (MAN Portable Air Defense) missiles, various cannons in barrel size and number of barrels, and Surface to Air Missiles (SAMs) that track aerial targets with radar or heat-seeking guidance systems. Many Air Defense systems have Air Search Radars (ASRs) or Thermal sights to aid in target acquisition.

Placing these systems where they can cover your forces and have a good line of sight to see enemy aircraft and helicopters as they approach your troops.

3.4.3 Anti-Armor

Another essential type of supporting force is dedicated anti-armor units. These are units focused on having the means to destroy enemy armor. There is a wide array of systems for these units as well. Infantry can carry Rocket-Propelled Grenades (RPGs), Anti-Tank Rifles, Recoilless Rifles, or deadlier Anti-tank Guided Missiles (ATGMs). There are also dedicated armored vehicles that mount ATGMs that provide the crew with safety and mobility.

Having these units in ambushes on the defensive or directly supporting attacking forces to deal out devastating attacks can swing the battle in your favor.

3.4.4 Command

Command elements are usually more static units that sit behind the other forces and direct the actions of their subordinate units. In some cases, these elements are part of the maneuver units in formations like companies and platoons and share similar vehicles to those in the main line formations.

While these units are generally weaker in firepower, their strength comes in being able to order forces and keep battle tempo. Losing these units can severely impact command cycles and lead to defeat as your enemy reacts faster to the situation on the battlefield.

3.4.5 Engineering

In many cases, your forces will need the support from engineering units to deal with water crossings, removing enemy mines and obstacles, and building fortifications (or removing enemy ones) on the battlefield. Engineers have specialized equipment and training to deal with these functions. These units are usually attached to your forces from higher-level units and are in limited numbers, and should be used carefully and kept out of harm's way when possible. See Section 4.7 below for some detailed information on Combat Engineering capabilities.

3.4.6 Recon

For any combined arms army to win on the battlefield, they need to know where the enemy is, what the enemy force composition is, and what the enemy's intent is. Counter-recon is the fight before the fight. Effectively using your recon assets to find the enemy recon and then the enemy forces should be the first course of action in any battle. Recon forces can and will call down artillery fire on units they spot. In some cases, they may have enough firepower to hold up or delay the enemy's main efforts while other units move up to engage. Use these types of units to scan as much of the battlefield as possible before the shooting starts.

3.4.7 Transport

Transports are those types of vehicles, like trucks, jeeps, and Utility helicopters, used to move combat troops and equipment across the battlefield. While these units are not part of a combat formation, they are utilized by commanders when available to move their combat forces to an area of need faster than on foot.

In the case of helicopter-transported troops, these are used for air assault operations and have the speed and flexibility to place your forces deep into enemy territory to secure critical objectives.

3.4.8 Supply

While not directly seen on the map as units, supply is a critical aspect of modern warfare where munitions are burned through at a rapid rate. Troops also lose readiness and morale as the battle rages, and to win many battles, knowing when to pull forces out of the fight to rest and refit is critical, and failure to act can lead to units running out of ammunition or troops being too tired to be effective in combat.