In part one I discussed why taking the midfield is important, and how you need to keep the midfield in mind when writing your list. This follow up will go into more depth and particulars regarding how to capture and hold the midfield.
The Why: A player needs to control the midfield for several reasons. Most basically, it puts you in a position to control the midfield objectives and to move to contest/control the enemy backfield objectives. That much is self-explanatory. Unless your army is fast skimmers with Star Engines you can't go from your backfield to your enemy's backfield in one turn, so some presence in the midfield, at least towards the end of the game, is required in objective missions. More in depth, controlling the midfield is the best way to protect your vulnerable backfield. A Rhino with popped smoke containing a multi-melta and a meltagun sitting in the midfield means that your opponent's armor cannot speed right into your backfield. Trying to get past your melta-bubble(s) without dealing with them first is certain death. Your opponent will have to devote at least two shooting phases (at least) to killing your midfield melta bunker. That is two turns where your backfield guns keep firing.
|Holding down the midfield.|
Against an assaulty army, midfield units play a similar role. Two Dreadnaughts sitting in the midfield is quite scary to assaulty armies. The last thing a unit of 30 Boyz or Genestealers want to do is get stuck in with a Dreadnought. Yes, the Dreadnought is probably not going to do anything for the rest of the game, but the fact is that their assault impetus is blunted. If you can get the assaulty opponent commited to a quagmire in the midfield, rather than your backfield, you're ahead. Lets say your opponent is using a Battlewagon with Nobs. You have a Dreadnought with Multi-melta in the midfield. Is he going to disembark to kill the dread in an assault and open his Nobs to a turn of unprotected shooting or counter charging? Is he going to drive past the Dread and take a rear melta shot? None of those options are exceptionally good. Remember: an assaulty army wants its first assault of the game to be in your backfield. If it's launching its first salvo 36" away from your backlines you are in very good shape.
The How: You want the midfield, your opponent wants the midfield. How do you make sure that you control it? The key comes in with how much of your long range firepower you can commit to winning the midfield without ignoring more important targets. Every map and matchup is different, but you have to decide how much of your long range firepower will be directed at the midfield and how much will be directed at your opponent's long range firepower. If your opponent has infiltrating assault units, or fast transports bearing down on your backlines, you cannot devote all your firepower to helping win the midfield, you obviously have to use good target priority. If your opponent has tons of artiller units in his backfield, you might have to silence those before you worry about helping the midfield. It is difficult to give hard and fast rules about this, but my advice would be to try to create a disparity. For example, if you each have 3 midfield units, use your long range fire to give yourself a 3:2 advantage, and then use your long range power for other targets. So long as you maintain even a slight midfield advantage your opponent will have to commit more resources to it than you, which is a win.
The Who: What constitutes a good midfield unit? Melta is king. Melta can hurt anything and is so deadly against vehicles that a single multi-melta Dreadnought in the midfield can lockdown a 30" bubble. No vehicle can pass through that bubble with certainty, nor can an assault unit come within 12" of the Dreadnought without first dealing with the Dread. So Dreads are very good in the midfield. A
|Not pictured: 3 dudes inside with meltaguns.|
Rhinos (of any flavor) or Chimeras with dual (or more) melta inside is very good. A smoked Rhino with melta inside will require a good amount of firepower to force the troops to out. Then a good amount more to kill enough of the troops to silence the meltas. This is all good. A single Rhino unit can thus suck up a good amount of firepower and still be a threat.
|Go ahead and try to pass over him while he is sitting in the midfield.|
Tyranids are a very good midfield army. They have a lot of very resilient units with medium range firepower. T6 beasts with multiple wounds and good guns bubble-wrapped by throwaway units means they can just sit in the middle and fire away until you deal with them, and much like Dreadnoughts, most assault units do not want a piece of them in close combat.
It bears mentioning, that some armies simply don't have strong midfield units, and they have to play a much less linear game, like the Eldar. Or Tau, who eschew the midfield for bubble wrapped units of long range firepower. There is no sense in fighting a battle you can't win over a resource you don't need.