Protoss often attempt to use Adept and Stalker to delay or deny Terran from completing the Command Centre on the low ground at the natural. How well both sides play out this early skirmish has a huge impact in subsequent events. This post discusses some of the simple solutions that I see pros use.

I know many want me to write about the recent rise of mech in TvP, but 51% voted for this post. I will write about mech in the future. This post took a lot more time than I expected.

Build orders on both sides

Terran

This article assumes Terran use either 15 or 16 gas Reaper expand. These two are the most commonly used openings. 16 gas Marine expand is probably the third most commonly used expand opening if you do not count fake proxy. If securing the low ground expansion is the only goal, 16 gas Marine expand is probably better than the two Reaper expand openings (you’ve three Marines in time by default – for example). I will limit the discussion to the Reaper openings in this post.

These are the default build orders for the two Reaper openings (tech to Factory):

15 Refinery

14 – Supply Depot
15 – Refinery
16 – Barracks
@100% Barracks – Reaper and Orbital Command
@400 mineral – Command Centre (@100% – Orbital Command)
@100 gas – Factory
@100% Reaper – Reactor
22 – Supply Depot

16 Refinery

14 – Supply Depot
16 – Barracks
16 – Refinery
@100% Barracks – Reaper and Orbital Command
@400 mineral – Command Centre (@100% – Orbital Command)
20 – Supply Depot
@100% Reaper – Marine
@100 gas – Factory
@100% Marine – Reactor

Protoss

There are two openings from Protoss that require special attention when securing the natural expansion on low ground. One is the Cybernetic Core before Nexus, which is a more economical opening of the two. The other is proxy one Gateway and have the other Gateway in main base. This is an aggressive two Gateway expand opening that aims to force a cancel on the Command Centre. You can argue it is a pseudo-cheese.

Clearly, there are other more aggressive openings, but a good answer to those would be to not build the Command Centre on the low ground. For example, Protoss can go for an economical Core before Nexus opening and make a Zealot to attack with the Adept (vod example). I want to focus on the two common Protoss openings.

Cybernetic Core before Nexus

There are two different variations for Cybernetic Core before Nexus. One builds the Gateway at the standard timing at 16 (more economical), while the other builds the Gateway at 13 (more aggressive). Since the Cybernetic Core is put down right after the Gateway completes, the economical one is down at 20 (example) and the aggressive one is down at 18 (example). You can tell which opening it is from a Scv scout. If the Cybernetic Core is placed at 18, it should be completed by the time the Scv (19 supply scout) goes into the main base. From Protoss’ perspective, the economical variation is more about defending against the Reaper than to delay the Command Centre.

Depending on ground travel distance and the location of the Gateway, the Adept should reach Terran’s natural by 2:35~2:40 for aggressive variation and by 2:45~2:50 for the economic variation (usually a 8 to 10 seconds difference). The simple question is then, what can Terran do to prepare for the Adept at these timings? What you can do depend on the resource you have, and that is dependent on the opening you use.

16 Refinery

When the Barracks completes, the 16 Refinery opening has 50 less gas and more mineral than the 15 Refinery opening. The extra mineral has immediate impact in the time frame when the Adept is getting across the map.

Based on the recent games, the most common reaction is to build two Marines after the initial Reaper. That is, instead of producing one Marine before Reactor, you produce two (or even three) instead. The three units can deal with the single Adept of the economic variation (see vod below). Nevertheless, you would want to make a Bunker after you put down the Reactor (or Tech Lab), because these units alone cannot hold against two to three Gateway units in the next skirmish. The Reaper could also buy a bit of time by forcing the Adept to chase after it in Protoss’ base when the Adept just spawned.

However, this adjustment of having an additional Marine does not do as well against the aggressive variation of Core first opening. The second Marine should be out in time just when the Adept reaches Terran’s natural. Assuming Terran win the micro battle, all the survived units should be well bruised, and they may not prevent the second Gateway unit (likely a Stalker) from killing the Scv that is building the Command Centre. At this time, the Reactor is still building, and you have a Hellion or a Widow Mine at best. The Command Centre may get delayed longer than you will like.

The other way is to build a Bunker next to the Command Centre and a Reactor right after you put down the second Supply Depot. The default Barracks production sequence is Reaper-Marine-Reactor (see above), and this basically swap the Reactor and the Marine around. You still complete one Marine production cycle, but you do it with the Reactor and that means you have two instead. The Bunker completes right before 2:40, so you can have a Reaper in the Bunker against an Adept that could reach at 2:38. You will have to pull the Scv away temporarily to wait for the two Marines to chase away the Adept. This is a safer option against both types of Core before Nexus openings. The shortcoming is that the Reaper has to stay on your side of the map temporarily. See the vods below. You can take a look at other recent games of INnoVation, as this is his go-to reaction.

15 Refinery

The above discussion of 16 Refinery revolves around how we can rearrange the mineral to ensure we have sufficient defence when the threat arrives. However, the 15 Refinery opening does not have as much mineral, and the mineral to gas ratio is meant to tech up quickly. This is the reason why the default 15 Refinery opening put down the Factory and Reactor early on. If you continue to make Marines and/or build a Bunker early with 15 Refinery, you might as well use 16 Refinery. Further, the second Supply Depot is later for this opening because of the Factory, so you will get supply block if you continue to make Marine. Thus, unless you delay the Factory, there is little room to make adjustment to the build order itself.

Then, what can you do? A simple solution is to build the Command Centre on high ground. The reason players favor to build the Command Centre on the low ground by default is that you do not waste time flying the Command Centre to the natural. But when you get more delayed by building it on the low ground than building on the high ground, it makes sense to make this adjustment. In below vods, Terran do not bother to send a Scv to scout with a 15 Refinery Reaper opening and just build the Command Centre on the high ground.

In my opinion, Reactor Factory is perhaps the only option that can justify building the Command Centre on the low ground. With 15 Refinery, you get to complete the Factory early, and you can switch it onto the Reactor to make two Hellion. You can push the Adept away with a Reaper and two Hellion. See vod below. I don’t know whether the delay on the Command Centre is equal to the delay with flying the Command Centre from the high ground to the low ground. They might be close.

Proxy second Gateway

The first Gateway unit should arrive at the natural at around 2:30. The key difference is the subsequent reinforcement of Gateway units with two Gateway production. From Terran’s perspective, the goal is more than just about minimising the delay, but it is also about how many workers/units you can afford to lose in the process. It would be silly if Terran can hold well with close to little losses against two Gateway with one proxy.

16 Refinery

If you want to hold the low ground, you must have a Bunker. You cannot just make an additional Marine or two like I mentioned earlier, because the reinforcement Gateway units would destroy that set up. More importantly, unlike the Bunker option discussed earlier, the Bunker should be built before the second Supply Depot against this Protoss opening.

Maru versus Classic in GSL 2019 Season 1 Final game 1 is the best hold against this strategy I’ve ever seen (read my review here). He basically squeezed in a Bunker before the second Supply Depot and then proceeded to do the standard things (see notation and vod below). The Stalker could still walk past the Bunker to delay Command Centre at the back, and that would become a micro battle. Terran would have to wait for more units and pull some workers to trade with the Gateway units.

14 – Supply Depot
16 – Barracks
16 – Refinery
@100% Barracks – Reaper and Orbital Command
@400 mineral – Command Centre (@100% – Orbital Command)
21 – Bunker
@100% Reaper – Marine
22 – Supply Depot
@150 mineral – Factory
@100% Marine – Reactor

The second option is what I like to do. It is sort of a combination of Maru’s method and INnoVation’s Core first reaction. I copy Maru’s Bunker timing, but I build a Reactor right after Reaper is completed (see notation below). I have one Reaper in the Bunker when the first Stalker arrives. Similarly, the Stalker can walk past the Bunker and delay the Command Centre from the back. The difference between mine and Maru’s is that I sacrifice the first Marine to get one additional Marine (i.e., two) with an early Reactor. This helps to deal with the walk past Stalker.

14 – Supply Depot
16 – Barracks
16 – Refinery
@100% Barracks – Reaper and Orbital Command
@400 mineral – Command Centre (@100% – Orbital Command)
21 – Bunker
@100% Reaper – Reactor
22 – Supply Depot
@100 gas – Factory

The third option is to build the Command Centre on the high ground. When the Scv scout at 18 supply does not see the Nexus, you can delay putting down the Command Centre on the low ground for a few seconds. The Scv should then go into the main base to see what the opening is. After you deduce that this is a proxy second Gateway, you can build the Command Centre on the high ground instead.

15 Refinery

Putting the Command Centre on high ground is obviously an option for the reasons I explained earlier. This is consistent with the rationale of not scouting with 15 Refinery opening and then put the Command Centre on high ground by default. If you cannot prevent the Command Centre from being drastically delayed on the low ground with 15 Refinery against any slightly aggressive Protoss opening, why not just build it on the high ground then?

If you follow through with the build order of this opening to put down a Factory and a Reactor, you have nothing but a Reaper (not even a Bunker). It is bad, period. Even the almighty Maru cannot do that (see vod below). He essentially lost game 2 against Classic in the GSL final because of this.

As mentioned earlier, you cannot afford to make Marines (immediately after Reaper) and a Bunker if you put down the Factory. I have seen Terran not building the Factory, and put down a Bunker, a Supply Depot, and produce Marine. But you would then bank up gas, and it results in a less efficient version of a 16 Refinery opening (see vod below).

In sum, with 16 Refinery, the Bunker reaction is the most versatile and easy to do. You can always build a Reactor after the Reaper, and then adjust the timing of the Bunker according to opponent’s opening. With 15 Refinery, just build the Command Centre on the high ground by default.

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This article is translated and posted on:

• NeoTV.cn by fdupioneer
• Baidu by 绝迹

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