"Tanks don't have brakes" - Heinz Guderian
First, what is Spearhead?
Spearhead is essentially a Recce Move (prior to turn one a Recce Move allows a unit to move up to its full move distance, but not at the double, as long as the unit does not enter to within 16" and in line of sight of another enemy unit, or within 8" of another Recce unit), but with one essential difference: when a unit makes a Spearhead move it must completely leave its deployment area.
Another critical note: Spearhead moves occur after all Recce moves have been completed. Keep this in mind because it is extremely important.
"@#%!" - George Patton
Obviously, Spearhead can be very powerful. It can give units, or even entire armies, a chance to rush the enemy positions before the opponent even has a chance to react. In Defensive and Mobile Battle missions, with the attacker almost always going first, it can lead to Turn 1 victories (most Spearhead armies also have the Always Attack rule). I have used it numerous times to overwhelm an opponent's flank so quickly that he cannot redeploy in time.
But, for you defenders facing Spearhead, there is a very simple fix incorporating something that every list should have in the first place, something that every army has access to:
American M8 Greyhound
British Universal Carrier
The answer is to have Recce Units. Recce moves alternate between players, but always give the defender the chance to make a Recce move first. Now, every army should have at least one Recce unit, because they're just that good in V3.
But the key to using them to stop a Spearhead move is to position them in such a way that you maximize their command distance and field of view. The more of the battlefield they can see, the better. On a terrain-heavy board a wise opponent will still be able to pull off a decent Spearhead move, but having those Recce units advancing forward onto hills or into fields can effectively shut down a Spearhead.
Example: a unit of Recon Jeeps (American in this case, although many armies have Recce units that move as jeeps). 3 Jeeps, rated Confident Veteran, so their command distance is 6" (not 8" for armored vehicles, which is what 8-Rads would get for example). That forms a 12" string of Recce vehicles which can advance up to 16" with a full move. I guarantee this will confound a Spearhead move by moving close enough so that an opponent travels roughly 2" before he's in Line of Sight of your teams. And if you have two Recce units, both of which get to move before the Spearhead, then you're in the zone my friend.
A single, 60 point unit of these can stop 14 Panzer IV's in their tracks
So the keys to stopping a Spearhead from wrecking your day:
1. Have Recon
2. Make sure that you choose to deploy your Recon units (defenders often have to choose what gets left in reserve, choose wisely!)
3. Try to gauge where your opponent will attempt his spearhead, then deploy your Recce units appropriately. look for hills that give a commanding vision of the battlefield, or clear lanes of approach around/through terrain.
4. Don't be intimidated! Spearhead is strong, but it isn't a game-breaker. Do not give in to fear! Play smart and you will be fine. You'll just have to use a little extra thinking power to defeat it.
By the way, most Spearheading armies rely upon it for the win. If you make a mess of your opponent's plans by following these steps, you are well on your way to victory.