TvZ: When and What to Scout for?

vs zerg

I was typing a long chunk of words about when and what to scout for while I was preparing for the last post (TvZ: Reaper Opening into 3CC). In the end, I removed it as the content deserves a post of its own and is too “general” for a specific build order. So here it is.

This covers the basics and most advance scouting knowledge. However, I will not go into a pro-level analysis, for example, count the number of Drones at a certain timing. One simple reason is that I’m just not good enough for that. The other reason is that metagame shifts constantly and methods like counting Drones are not viable unless you do Starcraft for a living.

Basic early scout

There are two basic SCV scout timing. One is to scout after the first supply depot is built, and the other is at 15 supply (usually when the barrack finishes). Flash likes to scout after his first supply depot is built in a two players map. This is because the time that the SCV reaches opponent’s natural is the time that he decides whether to build his command centre in the low ground or the main for his 14CC build. If there is a hatchery building at the natural, it is safe to have the command centre at the low ground. If there isn’t one, then you should use the command centre to wall off the main as it is a pool before hatch build. Other than doing a 14CC build or an engineering bay block, I do see much benefit of scouting with such an early SCV.

The 15 supply SCV is the standard scouting time. Similar to earlier SCV scout, the first thing to scout for is whether there is a hatchery at the natural. If there is no hatchery at the natural, simply wall off the ramp immediately. Next, move the SCV to the main to see what type of one base build the opponent is doing. There are mainly three possibilities:

  • 6 pool
  • 10 pool
  • One base Baneling all-in (Probably this has extincted)

Bunker is needed if it is a Baneling all-in, while wall off is enough for the other two possibilities. If there is a hatchery at the natural, it shapes up to a standard game.

If you open with a 12/12 Reaper, the Hatchery should complete right when the Reaper reaches it.

Quick sum: Is there a hatchery at the natural?

Hatchery first – Basic

The key is to scout for spawning pool and extractor. It is possible that there is no spawning pool in the base at that time, and that means it is a third hatchery before pool build. Just move the SCV around the base, as the opponent might simply delay the spawning pool. Check the third if there is no spawning pool to confirm if there is a third hatchery.

If there is a spawning pool, the next thing you need to scout is the timing of the extractor. There are three main possibilities:

  • No extractor
  • Extractor after spawning pool
  • Extractor before spawning pool

If there is no extractor, it will be an early third hatchery with four to six Queens.

Extractor after pool is the current standard build. The next thing to scout for is whether the first 100 gas is invested in speed upgrade. This can be known by looking at the animation of the spawning pool. The speed upgrade should start by 4:00. If there is no speed upgrade ,which is rare, there should be a roach warren for early Roach timing. For a hatchery-pool-extractor-speed build, there are two key things to take note:

  • Speed upgrade completes by 5:45 – 6:00
  • Third hatchery starts building by 6:00 – 6:30

Make sure your units are not outside out in the map by 5:45, as you do not have the map control. If you have Reapers, you can either bring them back to the base or sacrifice them to scout for tech buildings.

If there is no third hatchery, it could be a two base timing or a two base lair tech.

Extractor before pool is either an aggression build or a tech build. Speed upgrade will finish slightly earlier than 5:45. The key thing is to scout whether there is roach warren or a baneling nest. Either tech building should be down by 4:30 – 5:00. You should retreat to the high ground. If there is no tech building, it will be a two base lair build which is less common in the current metagame.

Example of extractor before pool timing: GuMiho vs. KangHo

Quick sum: What is the timing of the spawning pool and extractor?

Signs of an aggression timing or an all-in

One key sign is the extractor timing as mentioned above.

The number of Queens can tell you the build too. There should be two Queens if the Zerg player is doing a timing. A standard macro build usually has four Queens.

Creep spread is another sign, but it is harder to evaluate. If the Zerg player wants to do a timing, the energy of the Queen has to be spent on injection. Although some players suggest to check if there are multiple Overlords being produced at the same time, I find this really hard to catch.

If it is a hatchery-pool-extractor-speed build, the tech building should be down by 5:30. Most of the time it is a Roach-Speedling timing.

Example of Roach-Speedling timing: INnoVation vs. HyuN

The often misleading sign is the third hatchery. It is good to assume that a timing is incoming and play safe, when there is no third hatchery. Conversely, you assume that it is a standard macro game when you see the third hatchery. However, there are three hatch timings which can be fatal if you’re unprepared. A roach warren could start at the same time as the third hatchery, and shapes up to a Roach timing or Roach-Baneling timing.

Example of three hatchery Roach-Baneling timing: GuMiho vs. Symbol

It is difficult to tell if there is a three hatchery timing. If there are two evolution chambers being used as a wall at the natural, there should not be a three base timing. You really have to sneak a Reaper into the Zerg’s base or gamble on a scan to know.

A direct way to know if there is a timing coming is the number of Zerglings made. However, it is hard to objectively deduce how many is consider as a sign of a timing attack at various time frame, especially when Zerg players will try to hide the Zerglings.

Leave a comment if you have anything that you want to share about scouting vs. Zerg.


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