TvP: Reaper expand into three barracks


If there is one build you should learn in TvP, it is Reaper expand into three barracks. It is an all-rounder build suitable in any map. I will go beyond the basic build order and discuss about the upgrade variations in the early-mid game.

It is hard to state the weakness of this build. Perhaps its weakness is that it has no weakness, as it indirectly means that it does not excel in anything particular. Its predictability does allow good Protoss players to cut corners in the early and mid game.

Basic build order

10 – Supply Depot
12 – Barracks
12 – Refinery
15 – Orbital Command and Reaper
@50 gas – Pull Scvs out of Refinery
@400 – Command Centre (@100% – Orbital Command)
@100% Reaper – Reactor
@100 mineral – Supply Depot
@300 mineral – 2x Barracks. Put Scvs back in Refinery
@100% Reactor – Constant Marine production
@100% Barracks – Tech Lab on one of them
Build Supply Depot accordingly hereafter.

This is the basic build order for Reaper expand into three Barracks. Since this post is meant to be educational for newer players (this post is in response to request of some readers), I will elaborate more on the fundamentals.

It starts with a standard 12/12 Reaper opening. While the Barracks is producing the Reaper, it is important to pull Scvs out of the Refinery when 50 gas has been banked up. Since this build does not tech up to Factory immediately, we don’t need the gas beyond the Reaper. The 50 gas in the bank is for the Reactor. Since we have already invest in an early Refinery, it is more resource efficient to gather 50 more gas for the Reactor instead of pulling Scvs out earlier for another Barracks. For a single Reaper expand, we can afford to build a Command Centre before the second Supply Depot without supply block.

The Reaper will do its usual task of scouting. Build two more Barracks subsequently. These two can either be built one by one once you’ve 150 mineral, or both at the same time at 300 mineral. Put Scvs back into Refinery as we converge to a standard game.

I won’t discuss about how to react to opponent’s build as it’s not the purpose of this post.

After the Tech Lab is done, you can choose to upgrade any of the three bio upgrades. No matter which of the three variations you pick, the two base convergent point should be
– 3x Barracks
– 1x Factory
– 1x Starport
– 1x Engineering Bay


@100% Tech Lab – Stim and Refinery
@100 gas – Factory. Then, Refinery.
@175 mineral – Engineering Bay and Tech Lab on the third Barracks
@100% Engineering Bay – +1 Infantry attack
@100% Factory – Starport and Reactor on Factory. Start Marauder production.
@100% Tech Lab – Combat Shield
@100% Starport – Swap Starport onto Reactor and produce Medivac

Stim is the most main stream of the three. It is very similar to the Wings of Liberty one Barracks expand into three Barracks. The priority of upgrade should be in this order: Stim-Combat Shield-Concussive Shield. The +1 attack should be on its way.

Combat Shield

@100% Tech Lab – Combat Shield and start Marauder production
3 Marines and 1 Marauder per production cycle
@50% Combat Shield – Refinery
Stop Marauder production after 2, and continue only Marine production
@100 gas – Factory and Refinery
@100% Combat Shield – Stim and Tech Lab on third Barracks
@100% Factory – Starport and Reactor on Factory
@100% Starport – Swap Starport onto Reactor and produce Medivac. Engineering Bay

The Combat Shield variation requires the player to decide whether you are the offensive or defensive player. By that I don’t mean your play style, but based on what the Protoss is doing. If Protoss is going to attack, you have to defend. A simple and straight forward way to tell whether Protoss plans to attack is to check the geysers at his/her natural at 7:00. If they’re taken, then it’s likely that Protoss is tech-ing up and doesn’t plan to attack soon. This is not a perfect tell, but good enough based on my limited knowledge.

If Protoss is defending, you hit a Combat Shield timing with 2 Marauders and a bunch of Marines. Move out by timing the Combat Shield to complete by the time the units reach the opponent’s side. Try to trade as cost efficient as possible under Photon Overcharge. It is hard for me to explain what to target as it depends on opponent’s army position, composition, Force Fields etc. You have make decision on the fly. What to attack, where to move, should you move to the main etc. But never A-move the group by clicking on the ground, as the bio will hit the Nexus when the Photon Overcharge is activated. Kill as many units and Probes as possible. Before you attack, move your Reaper to Protoss’ main to split opponent’s army.

If Protoss plans to attack, make sure you know what you are defending against and prepare accordingly. Nevertheless, Combat Shield is arguably the best of the three variations in terms of defending at 8:30~9:00 timing against either Blink Stalkers or Immortal.

Concussive Shell

@100% Tech Lab – Concussive Shell and a Marauder
@100% Marauder – Move out with a Marauder and a bunch of Marines. Refinery
@100% Concussive Shell – Stim
@100 gas – Factory
@50% Factory – Refinery and Engineering Bay
@100% Factory – Starport and Reactor on Factory. Tech Lab on third Barracks
@100% Engineering Bay – +1 Infantry attack
@100% Starport – Swap Starport onto Reactor and produce Medivac

The Concussive Shell timing hits at 7:00. Similar to the Combat Shield timing above, send the Reaper to the main before you attack. The Concussive Shell allows you to pick off any Stalker on the way to opponent’s base. When you attack the natural, focus on killing units since you have the Concussive Shell. Simple. Since it hits at 7:00, look at the geyser at the natural to deduce what opponent is going to do.

Some of the building timing are adjusted slightly for better build order illustration. It is easier to memorise too.

5 thoughts on “TvP: Reaper expand into three barracks

  1. Hello Maxilicious. Im a newbie in SC2, only starting in bronze league. I like this build for practice my macro because is similar to 1 rax expand (recommended in Wol for newbies like me). In this stage, I only feel in capacity to play with only one build order for all the matchups. Then, my question is: Is possible to use this build (or your upgrade variations) vs Zerg or vs Terran. Can you comment about, please? If is possible, can you say me possibles adjusts?

    1. I don’t recommend to learn a build and use it in all match up, because it shows how much one doesn’t understand a match up and a build. However, if you’re a new player, I don’t see any harm to learn a single build order first in order to learn the basic mechanics of the game and race itself. Subsequently, learn one build per match up once you get more comfortable.

    1. The key is to look out for the geyser at Protoss’ natural. If they are not taken, then it is quite likely that Protoss plan to do an attack. So be prepared. The type of units you see will probably tell you what type of attack it is.

      If the geysers are taken, it is likely to be a macro game that Protoss did not plan to attack. However, since you’ve traded some units, Protoss may do a (soft) counter attack.

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