Mass Versus Mobility

"[Blitzkrieg is] The art of concentrating strength at one point, forcing a breakthrough, rolling up and securing the flanks on either side, and then penetrating like lightning deep into his rear, before the enemy has time to react."
-Field Marshal Erwin Rommel

Why 'Mass versus Mobility'? What does this mean?

I think that of all the games I've played, or watched, more have been won or lost due to mistakes made in the determination of which army is the Mass army and which army is the Mobile army, than for any other reason. Sometimes this mistake is made during deployment, but it also changes as the game progresses, and mistakes can be made in not correctly recognizing this.

So, why do I believe that this simple concept should be applied to every game? Because, the point system of the game supports that theory. A quick look at the army lists backs this up. Take the classic marine army for example. You can buy an assault marine, with a jump pack, for 22 points. You can buy the identical marine, without a jump pack, for 15 points. Applied to a 500 point force, the force with jump packs will have about 20 marines, while the force without will have roughly 30.

These costs are borne out throughout the game. A Seraphim costs double what a normal Sister of Battle costs. An Ork Stormboy costs 66% more than a Slugga boy. Consistently, through all the codicies, troops with enhanced movement abilities cost significantly more than models that simply march six inches each turn.

Furthermore, adding mobility to a unit of troops costs a significant number of points, even when the transport is as easily destroyed as an ork trukk, and adds no significant firepower to the army. Those are points which could otherwise be spent on more troops, and more guns.

Why would someone do this? To devote a significant number of points to mobility infers that mobility must be a good thing. And it is. A mobile unit is more likely to get the charge against a slower unit. A mobile unit can take greater advantage of terrain. A mobile unit can better capitalize on mistakes made by the opponent, or can more easily recover from their own mistakes. There is a reason that modern military doctrine places such an emphasis on mobility. (And one reason is that National governments don't have to worry about points, and seek to be both more massive and more mobile than their opponents).

With all the advantages of mobility, why would anyone not want to be mobile? Well, mass has its advantages too. Having more troops is a good thing (and this doesn't mean more troops in terms of models, but in terms of points). A more massive army is harder to destroy completely. What it lacks in mobility, it makes up in resilience. A more massive army can afford to sacrifice points for position during the game, in the form of sacrificed units.

By the nature of the game, one army will almost certainly have spent more points on mobility than the other. This army is the Mobile Army, while the other army is the Mass Army. The closer the two armies are to having spent the same amount of points on mobility, the less noticable the effect of this will become.

Furthermore, these roles can change in the middle of a game due to losses. A Mass army can trade units to destroy their opponent's mobility (transports), causing a reversal of roles midgame.

Both the Mass army and the Mobile army have certain tactics that can be used successfully, and others that will be used unsuccessfully.

Mass Army Tactics

The first tactic employed by a Mass army is castling after the term from Chess. It involves deploying, or relocating troops so that they are all able to support each other. If all the units can support each other, then the opponent (the Mobile army) will have a much harder time isolating individual units.

The castle does not have to be a static construct. In a Quarters game, the entire castle formation can move together towards the center of the table, such that some units fall in each table quarter. In an objective game, the castle can all move to occupy the objective. As such, the term 'castling' does not refer to a physical castle building, but rather the idea that each unit is supported by other units. There is no reason to force your castle to be a reactive strategy.

Also, a castle has to be designed with the opponent in mind. We know they're more mobile than you, but how do they intend to hurt you. A castle against a shooting-oriented army is different than a castle against an assault-oriented army.

Against a shooting opponent, you want to set up your units so that in order for your opponent to get shots against any one unit, they will have to come within line-of-sight of multiple of your units. See the section on Circles for a bit more about this, but basically, you want to put your shorter-ranged troops to the front, with the longer-range behind them, and fairly close together, so that your opponent cannot just take pot-shots against anything without having to sustain return fire.

Against an assault oriented opponent, their plan is largely going to consist of getting into assault as fast as possible, and then attempting to roll along your lines, consolidating from one combat into the next. So, while you want to keep your troops together, you want them far enough (7 inches) apart that fights cannot consolidate from one unit to another. You also want to be able to fire as much as possible at your opponent as he is sending his force towards you, so staying together to mass firepower is a must. You want your weaker troops on the outside, because when he does hit you, you want to have the fights end fast, allowing you more shooting. You also want your weaker troops on the edges of the castle, with any counter-assault units behind them, so that his charge bonus will be wasted on troops he could probably kill anyway, while your counter-charges will give your best troops more of an advantage when they fight. This sort of staggered castle will give you the best chance to shoot your opponent between close-combats, and give your assault specialists the best odds of turning the tide.

The second mass tactic is that of attrition. You can afford to take casualties if doing so will also cause casualties in the mobile army. In a one-for-one trade, the mass army will usually come out ahead, as they are likely to have more units to work with.

Mobile Army Tactics

A Mobile army takes the opposite approach. Rather than seek one-for-one trades, the mobile army looks for opportunities to engage significantly more of their force against a much smaller portion of the opponent's force.

One method of doing so is the tactic of Redeployment. A Mobile army is often able to move many of its units a considerable distance in a given turn. In some of the more extreme cases, every unit in a Mobile army is capable of moving a full 24 inches. This movement can be used on any given turn to redeloy the entire army to a more advantageous position. A frequent use of redeployment is to set up across the width of the entire table edge, hoping to lure your opponent into doing so as well, only to redeploy on the first turn, refusing one flank. When done correctly, this leaves a good portion of the enemy army left out of the fight.

Other tactics employed by a mobile army are used against the castle tactic, as presented above. Luring part of the Mass away from the castle with bait units is one example of this. Placing a unit that is worth victory points just outside the area that the castle can affect can cause some enemy units to leave the castle and attempt to collect the points from the bait. As soon as they're no longer supported by the castle, the Mobile army springs the trap, attacking the smaller split-off force with multiple units.

Another anti-castle tactic is the use of template weapons to cause the opponent to spread out their units. Once the units are spread out, it is easier to attack the flanks, as chances are good that the units on one side can no longer assist the units on the other side.

Misreading Roles

So what happens when you get it wrong? Well, it depends how you get it wrong. If you believe that you are mobile, you will deploy as if you are more mobile. Your units are likely to be spread out, so as to have the opportunity to pounce on any enemies left outside the castle. However, as you're really not more mobile in this case, your opponent will capitalize on your positioning, and will split your forces, as you had expect to do to them.

If you mistakenly think that you are the more massive army, you will go into the battle seeking a war of attrition, which your enemy will be more than happy to engage in, and win.

If you both mis-identify your roles, you'll have a strange game, until one of you stumbles into their correct role, and then wins.

If you both correctly identify your role, and play within it, you will find the most enjoyable, even games.

Conclusion

More so than any other distinction that can be drawn between armies, the one that I believe has the most impact on the battlefield is the distinction between the Mass army and the Mobile army. Far more than the distinction between shooty and assaulty armies, in that you can have a game with two assault armies, and one of them will still have invested more points into mobility than the other. In reality, most armies fall somewhere in the middle of the scale, and the differences will not be that extreme. But, there are extreme armies out there, designed to take advantage of opponents who do not fully understand the distinction. Most of these are extreme Mobility armies, as any army can simply focus on Mass by using only infantry models.

Extreme Mobility armies include: Mechanized Eldar, Dark Eldar, Ravenwing, and Speed Freaks. Each of these armies can be built in such a way that every single unit is capable of a full 24 inch move.