TvP Scouting + Early game guide/info dump with fact FE

Author: pand0r

This guide is by no means comprehensive. It covers roughly the first 4:30 of the game.

This guide is oriented towards players at 1600+ MMR. It still should be useful under that MMR range, but it's more important to focus on hitting your build. Why do I suggest 1600+ MMR? Because I believe that's the range where you should start thinking about making adjustments to your build.

Assumption:
We'll assume a 4p map for now. This guide will assume Terran is going 11 rax/12 gas, with scout on 13, going vulture first. If you're going rax cc, you typically scout on 12. We won't cover rax cc responses here.

In order to understand what you're looking for, you first need to understand how Protoss builds work. It can be helpful to look at your own TvP replays to see what P is doing, or try out P builds in single player.

P FE openers roughly fall into 3 different categories:

Zealot first openers

3 zealot, then goon
2 zealot, then goon

Core openers

Rangeless
Goon first
Core, zealot, goon (aka 1z1g, aka core zealot)

Nexus first openers (aka 12 nexus)

1 pylon 2 gate (2 zeal 2 goon)
2 pylon, 1 gate (2z 1goon)
2 pylon, 2 gate( 1z 2goon)
Nexus gate forge/Nexus forge

Here's some need to know numbers

Note:
Some of these do depend on P's build execution, so some thinking may be required when you see something strange

Zealots take 25 seconds to make
Goons take ~30(31) seconds to make
Zeal first = first zealot pops ~2:20
Nexus first = nexus finishes at around ~3:00
Core first = core is done by 2:35~2:40, 2nd pylon must also be done at this time in order to make a goon.
Goon is out at 3:10
With goon opening, range is done at ~4:40

After the initial opening, protoss will typically either go 2 pylon nexus (19-24 nexus, 3:00-3:40) or 3 pylon nexus (28-29 nexus, 4:00-4:20, 3rd pylon should be starting by 3:30 at latest).

Why does this matter? Because if you go 2 pylon nexus, you can make up to 2 goons before cutting workers to put down nexus, and then pylon, leading to a long delay between the 2nd and 3rd goon. With 3 pylon nexus, you can get out 3 goons immediately.

Furthermore, usually protoss needs to hold one goon back to avoid vulture runby. However, if protoss knows you don't have a vulture out on the map (either scouting or by picking it off), it is free for them to pressure you with all their units. On the other hand, if they go 2 pylon nexus and you see both their goons forward, you can sneak in the vulture to get in probe damage.

Pretty much all gateway openings except 3z1g can be done as either 2 pylon or 3 pylon nexus opening.

Finally, as a general rule, Terran wants to match expo timing with P to keep on econ, so if P goes 2 pylon nexus, you also want to do 2 depot cc. This is where the ebay block is a useful concept. If you know you can't match timing with protoss (say, vs 2z1g where you need to go 5 marine, with 3 depot), you can place ebay to force them to match CC timing. As a side note, this is also useful in gas steal situations where they open gate gas steal nex.

How to scout

Send scv out on 13 (12th scv). Scout either close position, then the other close position, then cross. This is also known as N scouting (Because it looks like an N, or Z on the minimap).

Considerations

If the probe comes in early (before rax is done), the first thing on your mind is the possibility of zealot. If you look at it from Protoss's perspective, they need to know where you are in order to send a zealot at you.
If zealot comes in very early (before marine is done) check for proxy immediately.

If you first scout (arrives ~2:30), you should see one of five things:

Nexus is making (nexus first)
Core is close to finishing, 80%+
Single gateway by first pylon (3z1g), or core at 50% (2z1g). Another indication is that core is starting by the second pylon (not near the pylon powering the gate).
No gateway (It's a proxy)
Zealot is blocking ramp

For nexus first, follow this guide (Don't cheese rush nex gate forge, it's a separate case entirely).

Case 2 is a core opener. In this case, it is very important that you keep your scv by the gateway as the core finishes, so you can see if a zealot pops out or not. Once you confirm that zealot or not, you need to look for the second pylon, which should be finished. At around 3 minutes, you can start leaving the base with the scv. If you see a nexus on the way out, it's rangeless. Check back at 3:30 to see if they've made a nexus + 3 pylon. Typically the 3rd pylon is used as part of natural wall, but not always.

To beat 1z1g, you need 4 marine + vulture or 3 marine + 2 scv + vulture. You just want to put as much damage as you can on the first zealot if they shove it in. Ok to pull 1 scv to help defend. Also ok to just run away. Zealot arrives slightly before 3rd marine is done, right about when factory finishes. Protoss usually wants to keep zealot alive to poke with probe + zealot + goon in this situation.

Case 3 is a zealot opener. You can leave the scv around in the base, check core status. If the core finishes at around 2:50, it's 2z1g. Otherwise, it's 3z1g. Consider ebay blocking. Bring two scvs to your ramp after your first marine pops to help. Zealot arrives right before 2nd marine pops, around when factory is 50% done(?). In 3z1g protoss will usually aggressively shove in their first zealot. Should pull SCV (up to 4) in this situation. Keep scv alive, don't take damage on marines. Make sure to rotate scv when health gets low. Important to right click zealot with scv, as a-move scvs turn stupid very easily. Fight around simcity, important to focus marine fire when multiple zealots. Usually if protoss backs up they will bring another unit with it, with the lower health zealot in the back, so check health and focus fire. Go 3 depot cc vs this. If you defend the first zealot perfectly vs 2z1g, you can go 2 depot cc (think of it as a 1z1g situation).

Case 4 is case 3, but zealot arrives even earlier.

Case 5, need early ebay (~3:50), check for proxies immediately, keep scv in natural.