This is a strategy for controlling an opponent's expansion while subsequently getting a straight shot at their base by creating a "wall" around them, keeping them locked in while still battering them. The first step in accomplishing such a tactic is knowing the map: Where are the entrances to an enemy's main base? If it's open, is it near water or landlocked? Is it on an island? The answer to these questions determines the means by which to block them. The easiest way to accomplish this would be if the enemy's base is in open terrain, with no mountains or cliffs surrounding it; or on a small island. For land blockades, the key units would be tanks, artillery, mobile AA, bots and, at later points of the game, experimentals (If the enemy was not destroyed earlier on). Keeping a circular wall of patrolling units will be able to shoot down out-going planes, and take down engineers or other units that try to escape. Artillery, meanwhile, will be able to pound their base from outside the circle, causing wide-spread damage. The strategy is essentially the same when blockading an island base, except that a large naval fleet would be key, with cruisers to take down aircraft, and destroyers and/or battleships to take out sea-borne units. For bases that have a more complex landscape, like on the Fields of Isis, where the bases are enclosed or have a more complex surrounding with water and land components, a mixed force is needed. It helps to close off any areas by which they could exit, preventing access to your own base or any external resources while expanding your own forces. An easier way to keep a blockade going, especially if the opponent fights back, is to start creating walls around the base, with point defenses, anti-air and shields. Obviously, this doesn't work on the water, but enough torpedo turrets and aquatic AA will do the same. This strategy is a good way to establish air, naval, land and resource superiority early on, and then hopefully maintain it in the late game.