TvZ: Reaper Opening into 3CC

vs zerg

I like Reaper opening in general as it gives me a sense of security in the early game. Previously, I have done Reaper openings against Terran and Protoss. This post covers the standard Reaper opening in TvZ.


Reaper opening is arguably the best build in TvZ now, and it can be played on any map. There are many variations and adjustments in the transition of Reaper opening in the metagame. The one that I cover in this post is the prototype of TvZ Reaper opening. It shapes up to a standard macro game with three command centres and double engineering bay. Subsequently, it will transit into the popular bio and Widow Mine composition.

Build order

10 – Supply Depot
12 – Barrack (@100% – Reaper)
12- Refinery
15 – Orbital Command
16 – Supply Depot
@400 mineral – Command Centre (@100% – Orbital Command)
@100% Reaper – Reaper
@100 gas – Factory
@50 gas – Reactor on Barrack
@400 mineral – Command Centre (@100% – Orbital Command)
@100% Reactor – Land Factory on the Reactor and build a Tech Lab using the Barrack. Produce 2x Hellions (constant production till three pairs)
@100% Tech Lab – Stim and Bunker
Constant Marine production.
@100% 3rd pair of Hellions – 2x Widow Mine (constant production till two pairs)
@250 mineral – 2x Engineering Bay (@100% +1 Attack and +1 Armor)
@75 mineral – Refinery
@300 mineral – 2x Barrack

The following build order varies according to situation and preference. Nevertheless, the build order should converge to 5x Barrack, 1x Factory, 1x Starport, 2x Engineering Bay and 3x Command Centre.

@100% 2nd pair of Widow Mine – Build a second Reactor using the Factory, and build a Starport. Land one of the two Barracks on the first Reactor. Build the third Reactor using the Barrack without an add-on.
@300 mineral – 2x Barrack (@100% – Build one Reactor on each Barrack)
@150 mineral – 2x Refinery
@100% Stim – Combat Shield
@100% Starport – Land Starport on the Reactor built by the Factory and produce 2x Medivac. Build Reactor using the Factory.
Constant Medivac and Widow Mine production.

It is hard to list the build order further as it varies depending on situation, which I will explain later. Again, the build order should shape up to the next convergent point by building additional 3x Barrack, 1x Factory and 1x Armory. Continue bio upgrade.


Let’s start with the Reapers. You can get one to three Reapers (two is optimum in my opinion), but they still serve the same purpose. The purpose of the Reapers is not to kill Drones, but to scout and force some Zerglings. In fact, it is impossible to kill any Drone. A good Zerg player will pull the Drone that you are targeting to the farthest mineral patch. The rest of the Drones will try to surround the Reaper if the Reaper walks into the mineral line and attempts to kill the injured Drone. Remember that Reaper takes five shot to kill a Drone. Thus, it is completely fine not to attack a Drone with a Reaper to begin.

When the first Reaper arrives at the Zerg’s base, the Hatchery should be building at the natural. If there isn’t one, wall off your ramp and scout the base to see what type of all-in is incoming. If there is a Hatchery at the natural, scout the main to see if the timing of the Spawning Pool and Extractor. The Reapers can be used to scout for various Roach/Baneling timing, which I do not want to go into details regarding when and what to scout for. I will do a separate post about that. Nevertheless, it is important to take note of standard speedling timing at 5:45 – 6:00, as it is the main obstacle when you try to scout for timing attacks. Taeja always brings his Reapers back to his base when speed upgrade is done, and only moves out on the map when he has Hellions.

With six Hellions and two Reapers, Terran player has the map control. Although ideally you want to deny creep with these units, Zerg players prefer to spend Queens’ energy on injection to produce more units and fight for map control in the current metagame. Still, you want to roam around with these mobile units as you will know if an aggression is coming. Zerg mixes in various timing attacks in the current metagame, and the mobile units can give you time to build bunkers. Although I state “Constant Marine production” above, it is important to produce Marauders if you scout a Roach timing.

mOOnGLaDe had mentioned on Meta that Zerg players consider Reaper opening into 3x Command Centre as greedy, and hence, they will do a timing attack early on with Roaches, and perhaps even Banelings. Such timing attacks are very common in WCS Korea and Proleague.

For example:

Terran has also made some adjustments to this build. One obvious adjustment is to build two barracks instead of the third Command Centre. It sacrifices economy for aggression, and has more units to defend against various timing attacks. GuMiho demonstrates this playstyle in WCS Korea Ro16 today in his three Zergs group. Another adjustment, which I have discussed in another post previously, is to get an early tank. GuMiho had even produced three tanks for early defense against Symbol today. Even if you aren’t sure if a timing attack is incoming, it is fine to produce one to two Marauders early.

There is no best way to reach the first convergent point that I have mentioned above. If you expect an all-in, you do not want to use the Factory to build Reactor, but use it to produce as many Widow Mine as possible. What I have stated above, the build order is just a general guide for a prototype build.

The purpose of the second factory is to get the Drilling Claws upgrade with a Tech Lab on it, while cosntantly producing two Widow Mines at a time with the first factory. I recommend INnoVation’s choice after you reached the first convergent point, and attempt to add three barracks and one factory to reach the second convergent point. INnoVation builds his second factory before the three barracks if opponent is going for Zergling, Baneling and Mutalisk composition. He wants to get the Drilling Claws upgrade early as it is significant against this Zerg composition. Conversely, he gets the three additional barracks before the second factory if opponent is going for a Roach and Hydra composition. Widow Mines are relatively less effective against such composition than a Zergling heavy one. Interestingly, I have not seen other Terrans making such minor build order reaction.

As for the three barracks, you can choose your add-on based on opponent’s composition. Personally, I get two Tech Labs (three in total for the eight barracks) if opponent goes for Roach and Hydra composition. If he chooses Mutalisk tech, I will get just one more tech lab to make it two in total.


This is a must-know build for TvZ. It allows you to scout timing attacks and potential all-in, while other builds have to gamble on scans. The various build adjustments play an important part to the metagame.

6 thoughts on “TvZ: Reaper Opening into 3CC

  1. Thank you a lot for this write up. I love that you list the build order items by minerals instead of supply / game time. The explanation is great as well. Time to start following this site!

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