Starcraft 2 TvZ Reaper Opener into Expansion Build Order

Home --> Starcraft 2 Terran Guide --> Terran Build Orders --> Reaper Opener (into Macro)

Click Here to Get The Osiris MethodOpening with Reapers in Terran vs Zerg has become a very popular strategy in Starcraft 2. In this guide, we are going to go over the build order for a standard Reaper opener into an early expansion.

This build is a macro build. We have a separate guide for using mass Reapers against Zerg in an attempt to put out pressure which can be found in our Starcraft 2 Mass Reaper guide.

Mass Reapers can be a fun distraction, but such a strategy is not viable at the top levels of play. Instead, Reapers are used early to for map control so that the Terran player can take their safely expand and control the map early on in the game. Since early Reapers into an expansion works very well in TvZ, we will be the focus on that build for this guide.

Reapers vs Marines: The Case for Reapers

Normally, Terran players who want to grab a fast expansion will use Marines and Bunkers to defend their base. Since Terrans can easily use Marines to do this, why would they want to open with Reapers instead? What advantages and disadvantages are there to using a Reaper opener?

The main advantage of opening with a Reaper is that the Reaper is faster than Zerglings without Metabolic Boost. In the hands of a skilled player, a single Reaper can destroy the Zerg's early Zerglings and then harass the Drone line until Queens come out or Metabolic boost finishes. With this map control, the Terran can grab their natural expansion safely without investing any resources in defense aside from that initial Reaper or two.

The Reaper also has the advantage of providing scouting for the Terran player. If you go for an early expansion and defend it with Marines, you really have no idea what the Zerg opponent is doing. The Zerg can use Zerglings to take down any scouting units so you are left in the dark. The Zerg could then do anything from grabbing a very fast third expansion to going for a Baneling bust and you would have no idea which one was coming.

With a Reaper opener, you can see exactly what the Zerg is doing. If the Zerg gets down a Baneling Nest or a Roach Warren, you know you need to quickly get out some Widow Mines or a Siege Tank. If the Zerg goes up to Lair or takes a third expansion, you know you can safely throw down a macro CC and focus on tech.

The downside to using Reapers of course is that they require vespene gas and are a bit slower to produce. This means that the Reaper opener is slightly slower from a macro perspective than going for a Command Center-first or a Marine-defended natural expansion.

If you are not sure what to pick, you could opt to learn how to play both styles, using the Reaper build below for 2-player maps and the economic Command Center First build for 4-player maps.

Reaper Opener into Expansion Build Order

10/11: Supply Depot
12/19: Barracks
12/19: Refinery (SCV production very briefly halted)
15/19: Orbital Command
16/19: Reaper
16/19: Supply Depot (added a bit early to complete wall-in at main base ramp)
18/27: Reaper
20/27: Command Center (you can place this right at the natural expansion. The Reaper gives you map control).
20/27: Factory

From here, there are several paths you can choose, and that depends on what your Reapers see from your opponent. For example, if you see a standard Zerg with 2 bases (possibly a third under construction) and no Roach Warren, Baneling Nest, or Lair, then you can safely move up to a standard macro CC as follows:

22/27: Reactor (on Barracks)
24/27: Command Center
29/38: Hellion x2

Your Hellions can then back up your initial Reapers, providing more map control against even Zerglings with Metabolic Boost and can be used to hold the creep in check while you macro off of your soon to be finished 3 Orbital Commands. If there is weakness and the Zerg is just macroing Drones hard, you can even poke in with your Reaper/Hellion combo and roast Drones or pick off a lone Queen.

If the Reapers scout a Roach Warren, you may want to add on some Widow Mines and a Siege Tank or two and skip the macro CC for now until after you have walled and fortified the entrance to your natural expansion. The unit choice you use depends on what you want to use the rest of the game of course. If you are going into mech, it makes sense to add Siege Tanks and another Factory or two, if you are going bio, add on more Barracks at this point and start getting your upgrades.

Controlling the Reapers

Understand that even if you do no damage with a Reaper opener, you are doing just fine. This build is designed to allow you to safely grab your natural expansion and perhaps a macro CC without staying in the dark. This makes it easier to defend yourself against Roach or Baneling busts as the Reaper can be used to scout out the Zerg early in the game.

However, if you do get some damage done with the Reaper, you have done well. Try to avoid Queens as best you can unless you are going for mass Reapers, as just 1-2 Reapers does not engage well with a Queen. It is better to ignore the Queen's low DPS and snag a Drone kill or two before fleeing to safety and healing up. If you can do this a couple times before the Zerg gets out enough Queens or Zerglings to ward you off, you can easily rack up 4-5 Drone kills. Good Zergs will pull away their weakened Drones and use them to make temporary structures, but this does not happen much until you reach the Diamond+ league.

Most importantly, do not lose your Reapers in an attempt to kill Drones. This is never worth it. The Reapers existence is to prevent enemy Zerglings from getting across the map and attacking your undefended expansion. If you lose your Reapers, you lose map control. It can take you a long time to get this map control back. At that point, all bets are off because when you lose map control early you do not just lose control of the map but control of the game as well.

Map Size

This build is great for any map of any size with any number of spawn locations. If I had to pick, I am partial to using it on 2 player maps. On four player maps, you can just as easily go for a Command Center first opener. Perhaps more importantly, your Zerg opponent is significantly less likely to go opt for a Roach or Baneling bust on a 4 player map, so scouting the opponent in the first few minutes of the game is less likely to reveal crucial information.


Opening with an early Reaper or two is an excellent way to gain map control as a Terran player in TvZ. This allows the Terran to safely grab an early expansion and check the Zerg's base for signs of an early attack, setting the Terran player up to effortlessly transition into the mid-game.

Click Here for The Osiris Method