There is much truth in “you can’t go wrong with a Reaper expand”, but there is more depth to a Reaper expand than many think. This post is about the variations of Reaper expand in all three match ups. This post does not cover scouting with Reaper, and the subsequent build order transtion. Also, proxy Reaper cheese will not be discussed, as the focus is on the Reaper expand opening.

Basic build orders of Reaper expand

Single Reaper

10 – Supply Depot
12 – Barracks
12 – Refinery
15 – Orbital Command and Reaper
@400 mineral – Command Centre
@100% Reaper – Reactor
@100 mineral – Supply Depot
@100 gas – Factory
@100% Reactor – 2x Marines

Double Reaper

10 – Supply Depot
12 – Barracks
12 – Refinery
15 – Orbital Command and Reaper
@100 mineral – Supply Depot
@400 mineral – Command Centre
@100% Reaper – Reaper
@100 gas – Factory
@50 gas – Reactor

Triple Reaper

10 – Supply Depot
11 – Barracks
11 – Refinery
14 – Orbital Command and Reaper
@100 mineral – Supply Depot
@100% Reaper – Reaper
@400 mineral – Command Centre
@100% Reaper – Reaper
@100 gas – Factory
@50 gas – Reactor

Explanation about build order differences

There are minor differences beyond just the number of Reapers for the three build orders above. A single Reaper gets an early Reactor, and hence, there is no unit building from the Barracks for a period of time. Thus, you can cut corner and put down the Command Centre before the second Supply Depot without getting supply block. The double Reaper needs to put down the second Supply Depot before the Command Centre, or it will cause a minor supply block. The triple Reaper is mainly used for TvZ. It goes for a 11 Barracks, 11 Refinery and 14 Orbital Command (11/11/14), instead of a 12/12/15. I will explain in the TvZ section below.

Terran vs. Protoss

I will cite Bomber’s Reaper expand way back in early Heart of the Swarm in 2013 as the prototype. 15 gas expand 1-1-1 was the norm before Reaper expand became the default opening in TvP. The initial Reaper expand was built on the idea of one Barracks expand into three Barracks build way back in Wings of Liberty, but made a minor change to start with a Reaper in the beginning. The Scvs are pulled out of the Refinery after 100 gas has been mined for the Reaper and Reactor, and it shapes up to a standard three Barracks transition. The single Reaper expand into three Barracks transition pulls Scvs out of the Refinery, and it is different to the build order listed above. The single Reaper expand above does not pull Scvs out of gas and shapes up into a 1-1-1. It usually turns into a Widow Mine drop transition. Nevertheless, the purpose of the Reaper is to scout, and it is particularly effective when you think that opponent may have a proxy somewhere. In line with this thinking, there was a period of time that Terran go for a Reactor for the first 50 gas, and get two Reapers to scout the map for proxy. In general, only a single Reaper expand is used in TvP, because a second Reaper doesn’t add any value. Interestingly, however, a second Reaper could be effective if the Scv scouted Protoss is doing a Nexus first. This is because the Gateway is later than normal, and two Reapers will be almost uncontested without a Stalker or Mothership Core. A second Reaper is a reaction move, and I will discuss how Scv scout allows you to make a decision on how many Reapers you make. Articles to read

• 3 Barracks
• Early +1 upgrade
• Widow Mine drop (Part 1 and Part 2)

Terran vs. Terran

Reaper expand is one of the more difficult builds in TvT. It requires great understanding of the build pool to deduce the possible builds, and then makes the best reaction possible (offensive or defensive). There are two misconceptions that I want to clear up. First, you should not Scv scout on a two player map with a Reaper opening. Second, while Reaper expand is reactionary in nature, the “reaction” starts after your Reaper scouted the opponent’s base. Both misconceptions can basically be discussed together. It is a good idea to do a Scv scout on a two player map, because you want to know opponent’s opening before your Reaper is out. I usually do a 14 supply Scv scout on a 2 player map, and the Scv will reach opponent’s base early enough to give me time to make an opening decision. If the Scv scout tells you that opponent is likely doing a proxy Barracks build, you cannot put down a Reactor after the Reaper (Single Reaper expand). Most of the time, you need to constantly make Marines against proxy Barracks no matter how extreme it is. Similarly, if the Scv scout tells you that opponent is not doing a proxy, it allows you to make a decision on how many Reapers you make. If opponent is doing anything other than a Reaper opening, you should do a single Reaper expand. In other words, put down a Reactor right after the Reaper. This is because a second Reaper does not do much, so it is better to get Marines instead. If opponent is doing a similar Reaper expand opening, you should not stop at one Reaper. The Reaper count is critical in Reaper opening mirror match, and stopping at one Reaper can lose you the game. It is not that uncommon to loss the one Reaper against two Reapers, and this will then snowball out of control because the one Reaper player will have nothing in base with the Reactor just completed.

How to adjust the build order after the Scv scout? The first Reaper should be about to come out of the Barracks when the Scv scouted opponent’s base, and the building structures at home can shape up to either single or double Reaper expand build. 10 – Supply Depot 12 – Barracks 12 – Refinery 15 – Orbital Command and Reaper You can put down a Supply Depot and continue building another Reaper after the first Reaper if the Scv scout confirms that opponent is also going for Reaper. This is a reaction against Reaper mirror. Thus, going back to the two misconceptions I mention, Scv scout allows you to make opening adjustments early.

In the above vod, Bunny used Reaper expand in game 1 and 2, and he scouted with an Scv. In game 1, Beastyqt was also doing a Reaper opening, so Bunny build a second Supply Depot to go for a double Reaper expand build. In contrast, in game 2, Bunny scouted Beastyqt was doing a gas first opening, he decided to go for a single Reaper opening. It is optional to go for the third Reaper if opponent is going for Reaper too. However, if you pre-planned to go for three Reapers, it is better to go for 11/11 (see above). GuMiho did just that recently against MMA (see vod below).

Further, it is a common knowledge to not move your first Reaper across the map, and position it on top of a ramp along the path that connects both players’ bases. The vod above sort of shows the mind game with the Reapers versus Reapers positioning. Sometimes you just blindly assume opponent may be going for Reaper opening too, then move out if nothing is coming your way. Both Dream and Reality were blindly positioning their Reapers on the ramps even though they didn’t know opponent’s opening in the vod below.

Of course, you can also do a classic two rax Reapers if the map allows.

Terran vs. Zerg

Reaper opening in TvZ is arguably the most interesting of all three match ups. While Reaper generally fills the scouting role in the TvP and TvT, Reaper can also apply early pressure and potentially kill some Drones. Thus, it is more common to have more than one Reaper in TvZ than in the other two match ups. Retrospectively, it is common to get either one Reaper or two Reapers in TvZ, and I have discussed some of the things to consider previously. For example, the mind game to position the second Reaper to defend against Zerglings counter attack on the Scv building the Command Centre. Anyway, more importantly, the build order trade off for the three build orders stated above affects how well the different openings line up with some builds. Let’s start with the popular triple Reapers. The key difference lies with the Barracks and Refinery being built at 11/11 instead of the usual 12/12. Every Terran player knows that 12 is the standard Barracks timing, and you have to wait for a while to get the 150 mineral at 12. Conversely, if you do not build a 12th Scv, you have 150 mineral to build the Barracks right after the Supply Depot. Thus, this build favors getting the earlier Reaper over the getting an earlier Scv, and this allows the Terran player to apply pressure earlier.

The next question is, why not do the same for single and double Reaper expand in TvZ? The rationale behind this is to get more out of the third Reaper and to align with the early game strategy better. When the triple Reaper started to become popular, it was done with the usual 12/12, but people figure out that the time for the third Reaper to contribute to the early Reaper pressure is too short. This is because Reapers have to retreat back to base when the speed upgrade of Zerglings finishes at 6:00. Therefore, in order to do as much as you can with the three Reapers, it is better to do a 11/11.

While all three Reaper builds can go for an early three Command Centre build variation, the single Reaper opening is least smooth out of the three. An early three Command Centre build usually put down the third Command Centre before the Factory finishes, and a single Reaper cannot do that unless you pull a Scv out of gas temporarily after you put down the Factory. If you compare the single Reaper and double Reaper builds, the difference in the resources spent is that 50 mineral (single Reaper) vs. 50 gas (double Reaper). It is this small difference that makes it less smooth for a single Reaper opening to move toward a three Command Centre build. Despite single Reaper expand’s shortcoming in three Command Centre build, it has an advantage in other offensive builds. The early Marines help to hide the build you’re doing by deterring Overlord scout. In line with this, an offensive build such as a Hellbat timing usually does not get an early third Command Centre, and the option to get either one or two pairs of Marines opens up more build alternatives. The Factory is not completed yet when the first pair of Marines is out, but the second pair of Marines is not out when the Factory finishes. Hence, the player has an option of whether to have two more Marines and delay the Hellions slightly. Some build orders will benefit from the second pair of Marines, for example, the 7:00 Hellion run-by and Marine drop. Articles to read

• 7:00 1-1-1 Hellion and Marine drop
• Reaper opening details