This is a common opening strategy in StarCraft II beta, there are variations of this build, but this is the most economical one. The goal is to have a very solid economy for Roach production very quickly, yet be able to defend most 10pool and Roach openings. It is best applied for ZvZ, but can also be used ZvT versus Marine/Reactor or Hellion/Factory openings as well as ZvP for 2 or more Gateway Zealot rush openings.
Basic Build Order
Upon completion of the Roach Warren you will usually have 1 free Larva, depending on the opponents action you may make a drone or Roach here. Shortly after the Queen's Spawn Larva should finish on the Hatchery, again depending on the opponent you may make drones or Roaches.
It is common for this build to get Lair tech in ZvZ very quickly after about 5~ Roaches are created to defend the ramp/choke. 5 is a good number because 5 Roaches will do 75 damage in a single volley(after armor reduction) to another Roach, and a Roach has 145 hit points (2 volleys will score a kill). Once at Lair tech, you will need
- Roach Speed
- Morph an Overseer (for detector to keep with your Roaches, to spawn Changelings to scout, and to itself scout with the speed increase)
It is arguable to get Overlord speed upgrade next as well for 50/50.