The OCS is a model of the mobile battle. It places emphasis on the principles of maneuver warfare theory (preemption, dislocation, and disruption) and punishes the player who pursues a purely attritional approach to warfare. Through its combination of logistics, command and control, and combined arms sub-systems, the OCS provides the most complete portrayal of mid 20th century operational combat yet achieved by a board wargaming format. Part of the OCS's appeal is the way it allows a player to take control of all the aspects of his forces. From logistics planning to entrenched infantry defenses to marauding armored spearheads, few games allow players to delve into so many varied and yet intensely important decisions while remaining eminently playable.

One of the aspects of operational warfare that has come to dominate military philosophy in modern times is the use of air power. In its infancy during the First World War, the use of the airplane in armed conflict during the Second matured to such a degree that near the end of the war in Europe the phrase "Aluminum Overcast" was coined to describe the absolute dominance of Allied air forces in the skies of the former Third Reich. But in board wargaming, air power has often been given rather shoddy treatment.

Most often treated as long range artillery, or even more abstractly as "column shifts" and "transport points", very little attention has historically been paid to developing a model of operational air combat anywhere as near as detailed as the armor, artillery, and even logistics considerations of most wargames. And those attempts that were made almost invariably fell far short in terms of either playability or realism.

Enter the OCS, with its tracking of aircraft down to groups of 45 planes, on-map movement and combat, and its wide selection of air missions. It's all there: you can provide CAS, blow up railroads and ports, conduct fighter sweeps, and disrupt enemy supply lines and depots. But among all of those juicy choices that can be used in conjunction with armor columns, artillery barrages, and infantry assaults, there is a little used and underappreciated air mission which practically screams to be recognized - interdiction.

Read the rule covering interdiction and it's easy to see why this particular mission is so easily overlooked. What's the big deal with denying the enemy the benefit of a road movement rate? And sure, I might be able to force the enemy to retreat underneath an interdiction zone, but that sure is alot of bother for an uncertain and dubious return on my air mission investment. Wouldn't it be better to use that fighter on a hipshoot, or to blow up that ammo dump, or try to knock down those enemy fighters on station?

The answer of course is that it depends. If there's one unifying lament of every OCS player, it's that there is NEVER enough supply (and seldom enough units) to do even most, much less ALL, of what you'd like to do. Faced with the overzealous tax accountant that is the logistics system of the OCS, most players will choose the most obvious and nearterm return on their SP investment that they can.

Sadly, for most players, that means blowing things up. And what could be more fun than that? It's easy to count dead enemy units or destroyed truck and supply points and tell yourself that you've hurt the enemy. But in most game situations, physical destruction is only a means to an end, not the end itself. Or to put it another way, destroying the enemy is NOT the same thing as defeating the enemy, and at the end of the day (or the game) if the enemy still holds the ground that YOU need to control, you lose. This isn't to say that destroying the enemy is a bad thing; only that it may not be the BEST thing in every situation, or the best way to use your relatively fragile air forces.

Accepting that wholesale destruction doesn't always lead to victory, the question to ask is what can interdiction do for me that other air missions can't? The answer is that interdiction is a tool that shapes the battlefield. For a tactical analogy, interdiction is like the well-placed minefield. While it can destroy a stupid or careless opponent, its best use is to make the enemy act in ways that he would rather not act. When used optimally, interdiction's primary value is in either preventing the enemy's forces from reaching a fight quickly enough, or in requiring the enemy to keep his mobile forces closer to the frontline than he would otherwise wish.

What constitutes "optimal" use of interdiction? Several facets of technique are necessary to properly employ interdiction, the first of which is rather obvious; you must establish air superiority (even if only locally) in order for interdiction to have a hope of success. Without it, your interdicting aircraft will be swept from the skies, possibly with severe losses, derailing your efforts before they even have had the chance to begin.

Second, and much less obviously, your enemy must rely on highly mobile mechanized or motorized forces for either his defense (if you are on the attack) or for his offense (if you find yourself defending).

Interdiction has little affect on leg mobile units, for two primary reasons.

First, infantry is best when fighting in terrain that is already difficult to move through. On average, interdiction just won't slow down an infantry unit enough to matter.

Secondly, infantry's relatively low movement allowance means that it will seldom be seen at the head of a deep penetration column or acting as a centralized reserve.

In summary, infantry is already slow, and making it slower doesn't reduce its effectiveness all that much.

Third, the enemy must be relying on the increased mobility afforded him by a road network. Remember, interdiction raises the MP cost to enter a hex to AT LEAST 1 MP, and the only terrain features that offer MP costs below 1 are roads. The obvious conclusion is that interdiction will have little effect on enemy units that aren't using roads to increase their effective movement rate.

Fourth, you much choose an axis of action - decide in what direction you want to force the enemy's units to move. On the defensive, use interdiction zones to encourage enemy units to move into terrain where they are less effective, and then counterattack him there. Don't forget that you can interdict areas behind friendly lines as well as behind enemy lines. The trick is to force the enemy to choose between fighting under/through interdiction zones (slowing him down) or fighting through bad terrain (slowing him down). Either way, with time on your hands, you can concentrate your reserves to deal with the threat, which in turn means that your reserve units can each be in a position to cover more effective real estate, as they can afford to be farther behind the front lines and therefore more centrally located, not to mention outside of barrage range of enemy artillery.

On the offensive, choose where you want the enemy's reserves to move when he's reacting to your attack. The properly placed interdiction zone will either dislocate his reserves by preventing them from reinforcing the front rapidly enough, or will force him to place his reserves closer to the front, making him more vulnerable to artillery barrage and spoiling attacks. For example, the typical armored unit has between 6 to 8 MPs in combat mode (3 or 4 in combat reserve mode). Taking advantage of a road net, that unit could easily be located 6 or more hexes behind the line and still be able to move far enough during the reserve phase to reach the front and counterattack or plug a hole in the line. But if only a couple hexes of that road net are covered by an interdiction zone, the unit will find itself too far away to reach the front line during its reaction phase.

To account for this possibility, your opponent is either forced to place his reserve unit in move mode (reducing it's combat power) or move it closer to the front. Even if your opponent does chose to place his reserves closer to the front in order to preserve their individual combat strength, he will either require more units to provide adequate coverage, or will be forced to accept having fewer reserves then may be prudent.

In effect, he will be trading local combat strength for reduced operational agility and reduced overall combat strength. Note also that no matter whether you're attacking or defending, enemy units will be generally located between your ground units and your interdicting air units. Subsequently, any retreat result on the CRT threatens to force enemy units back through interdiction hexes, increasing enemy losses.

Another appealing aspect of interdiction missions is that they violate one of the principles of air warfare in the OCS as pointed out in a previous Operations article (see Ops 37, "Up in the Air" by Dean Essig). This general case is that, in order to be effective, an air campaign must concentrate effort over many game turns.

If you want to reduce a port, attack the supply lines, kill panzers, or destroy aircraft at their base, you need to commit a significant portion of your air assets each and every game turn, for several consecutive turns, to realize a noticeable effect. It is ironic that air power, a tool ideally suited to maneuver theory, is at its heart attritional in nature.

But interdiction is different. Unlike the other air missions, interdiction is not at all attritional. Rather than measuring success in step losses or SPs destroyed, it is best judged by how it influences enemy movement. For this reason, one well placed interdiction zone at the right time can pave the way for the destruction of many more enemy units then a single hip shoot could ever hope to manage.

Interdiction is also a great way to get the most out of otherwise ineffective air units. Even a couple of lousy fighters that would be cannon-fodder in air-to-air combat can often be combined to muster the total GS rating of 3 that is needed to establish an interdiction zone. And since a single interdicting aircraft stack can affect 19 hexes of land area, even if you are forced to use more than one aircraft unit to establish an interdiction zone, interdiction missions can still yield a very big bang for your SP buck.

Also because of this non-attritional, no build-up necessary nature, there's no warning to let the enemy know when you might spring an interdiction zone on him. Should he prepare for the possibility as part of his overall operational strategy? Should he establish more patrol zones to prevent your interdicting aircraft from setting up in the first place? Place his reserves closer to the front? Prepare fighter sweeps to send your interdicting stacks to ground? If he does any of these things, he'll practically be doing your job for you, since he'll constrain his operations as if you had already committed your own resources to interdiction missions. But if he ignores the threat, he will leave himself vulnerable to having his reserve units functionally dislocated or disrupted. Especially at times or in areas where air superiority is still being contested, these sorts of no-win decisions can force a player to make all sorts of concessions that impair his overall plan.

Not only does he have to deal with a threat - he has to deal with POTENTIAL threats, and the more such phantoms you can throw his way, the more considerations you force him to analyze, the greater the chance that he'll make a mistake. Providing your opponent with one more fish to fry is never a bad thing.

Finally, one last aspect of interdiction which is so appealing (especially to those of us who are perpetually "dice challenged") is that there is no element of random chance involved in how effective an interdiction zone will be. Once you establish a zone, it ALWAYS affects enemy units moving through it. No dice to roll, no snake eyes to foil your meticulously crafted plans. If there are roads and enemy units moving on them, they will be slowed down. Considering the wide range of fortune that can be inflicted on either side during the course of even a single game turn in the OCS, this non-probabilistic feature of interdiction is quite refreshing.

So there you have it -- an analysis of interdiction in all its glory. I hope I have demonstrated how interdiction is a subtle and precise tool of maneuver warfare theory, best used sparingly if at all. It isn't a magical, war-winning, universally applicable tactic - far from it. Interdiction is but one weapon in your maneuver warfare armory, albeit one which offers a potential return on your investment far in excess of the resources that you commit to it. So the next time you develop an air plan to support your hordes of panzers (or to destroy hordes of panzers), remember that the principles of maneuver warfare theory apply to the air as well as the ground, and look to see whether a few well placed interdiction zones won't serve to throw your opponent's operations into a tizzy better than one more hip-shoot or yet another low-odds barrage of a supply dump. You may be surprised at seeing your opponent's reaction if, suddenly, his reserves can't quite make it to the battle in time. Happy hunting.