Newer players often ask me about scouting and what to do if they see certain things when they scout. The idea of this article is to do exactly that and give you some intel on what to expect depending on what you see with your initial scouting worker. Most of the time when you scout you’ll see a standard build (i.e. 1 Rax building, 1 Gas building or complete for Terran, 1 Gateway Finished 1 Cybernetics Core Building for Protoss), which doesn’t tell you anything other than that they’re probably not cheesing. In cases like this follow-up scouting, scanning or unit poking is required to figure out what they’re doing.

In all other cases you can get a reasonably strong idea of what they’re doing simply from their initial buildings the timing and positioning of them. This article is aimed at listing those cases and what to look for. Please feel free to comment and add your own info, screenshots, corrections and questions and I’ll be sure to add them to the list.

Note that most of these cases assume that you’re spawning on close positions or on a 1v1 map and you should adjust for cases where your scouting is delayed for whatever reason. Similarly, some builds are only practical vs certain races (for example 6 pool is more common vs Protoss but might be seen in any matchup) and I’ve tried to mark these cases (in red).

Scouting vs Terran
Supply Depot & Barracks at BOTTOM of ramp – Hiding something: usually 2-Rax or Banshees.
1 Rax no gas – 1 Rax FE, 2 Rax FE, 4-7 Rax All In.
1 Rax 1 gas – 2/3rax aggression or Marines+Hellions+air.
1 gas Before Rax – Banshee Rush, Reactor Hellions.
2 gas 1 Rax – Banshees, Blueflame Hellions, Tanks, Thors, Raven… mass Reapers? So many possibilities!

Scouting vs Protoss
No gas, no Gate, no Pylon = Proxy Gate or Cannon rush.
No gas, no Gate, 1 Pylon and chrono boosting probes = fast expand.
No gas, Forge = Cannon rush, Forge expand (only common vs Zerg).
No gas, Gateway(s) = Zealot rush.
1 gas, 1 Gateway = 4-Gate or 1-Gate expand (keep your scouting worker alive as long as possible).
2nd Gateway before 2nd gas = 4-Gate or (vs Terran) 2-Gate expand.
2nd gas before 2nd Gateway = Teching (Stargate, Robo, DTs…) or (vs Zerg) 3-Gate Sentry expand

Scouting vs Zerg
5/6 Drones on minerals & Finished Pool = 6 ling rush (more common vs Protoss but can affect all races).
Gas before Spawning Pool = Fast Zergling Speed, possible Roach/Baneling bust.
Early gas + Spawning Pool = Baneling aggression.
Early gas + Evolution Chamber = +1 Attack Speedling timing attack.
Inbase Hatchery before expand = Mass Zergling all-in attack.
1 Base, double Extractor before starting Lair = Strong chance of quick 1-Base Mutalings.