Basics of the 6-pool Rush
Zergling rushes are very popular in Starcraft 2 because they are easy to do and often difficult to defend against. The Zerg 6-pool strategy - which involves not building any drones until after a spawning pool, getting zerglings out very quickly - is especially troublesome because most standard builds will not have any troops or defensive structures built, forcing the player to defend with nothing but workers. The plus side is that your workers can handle Zerglings, but the 6-pool can be a problem if the opposing player has high APM or very good micro, or if you are not paying attention when the zergling rush comes. The following sections have guides for defending the 6-pool if you fail to fend off the initial rush with your workers.
Defending Against the 6-Pool as Terran
Defending the 6-pool cheese is perhaps the easiest as Terran due to their ability to wall off and the strength of the Marine - when combined with good micro - against Zerglings. As usual, you should be scouting often and early - if you see a fast spawning pool, either rush your wall off by building a second supply depot quickly or start building a bunker. You may have to send SCV’s to repair while you wait for your Marines to come out, but if you can finish your wall, you will have stopped the attack dead.
If the Zerglings get into your base, don’t panic. Defend with your SCV’s if you can, trying to surround the Zerglings whenever possible. You may lose some, but your economy will still be stronger than your opponents. Once your Marine comes out, micro him to keep him alive, or use SCV’s to tank while you kill the Zerglings from afar with your Marine. After you’ve cleaned them up, finish your wall off, build more Marines and prepare for the next wave.
Defending Against the 6-pool as Protoss
Beating a Zergling rush as Protoss is simple, but the timing can make a big difference because of the relative slowness of Protoss defense. If you scout a Spawning Pool early, you will want to throw down a Gateway as quickly as possible and abandon plans of teching and go straight for Zealots. One Zealot will not kill six zerglings, but two - combined with probes - will give you an excellent chance of defending the 6-pool rush. If the Zerglings arrive quickly, micro your probes to kill them - their shields mean they can take a beating and still contribute, so try to pull back weak ones andd let them heal. Have your probes run interference for your Zealots, who tear through Zerglings. After you’ve defeated the rush, pump more Zealots, warp in a Forge or simple continue teching.
Defending Against the 6-pool as Zerg
Beating a Zergling rush as Zerg is perhaps the simplest of the three races in Starcraft 2 because you too can simply produce Zerglings to match your opponent - however, if you are going a macro heavy build or early expand and do not scout, you can easily be caught by surprise, so use your Overlord and a drone to make sure you know what your opponent is doing. If you scout an early Spawning Pool, simply build one of your own and rush out six Zerglings - even if your opponent is fast, they should arrive at a similar time since your foes’ have to run across the map. Even if they’re slow, just defend with drones until they arrive, then build a Queen, Spinecrawlers and consider teching to Roaches, which destroy Zerglings.