ByuN’s Revolutionary Builds

ByuN is well known for his micro and emotion but rarely for his unique ability to create paradigm shifting builds. This post discusses three builds that challenged our assumptions.


Most of us are familiar with the 2-1-1 build, and ByuN was often credited it. The build aims to load up 16 Marines into two Medivacs at around 4:45 and attack with Stim by 5:00. The basic 2-1-1 build was the most common TvZ build back in 2016, and I had written multiple articles about it. See vod below for the basic version of the build.

14 – Supply Depot
16 – Barracks
16 – Refinery
@100% Barracks – Reaper and Orbital Command
@400 mineral – Command Centre (@100% – Orbital Command)
@150 mineral – Barracks
@100% Reaper – Reactor
@100 mineral – Supply Depot
@100 gas – Factory
@75 mineral – Refinery
@100% Barracks – Tech Lab (@100% Stim)
@100% Factory – Reactor and Starport
Constant Marine production and build Supply Depot accordingly hereafter
@100% Starport – Swap it onto the Reactor of the Factory and produce 2x Medivac
@250 mineral – 2x Engineering Bay

The build was influential in changing our conventional wisdom in several ways. First, it opened our eyes of what we could do with the accelerated economy of Legacy of the Void. In Heart of the swarm, after one Barracks expand, Terran usually chose between building up a bio army or getting tech (other options were less popular). Players understood that they do not have the resource to build up a bio army with Stim and tech up to Medivacs at the same time. Picking one over another was an important strategic choice, but the opportunity cost of such decision is lowered in Legacy of the Void. The 2-1-1 build is the result of the accelerated economy in Legacy of Void, as players can efficiently get 16 Marines (with Stim) and two Medivacs simultaneously without choosing between army and tech. Being able to build an army and tech up simultaneously sounds elementary now, but players were still shackled by the assumption of focusing on either army or tech in 2016 (early Legacy of the Void era).

Second, the build challenged our assumption in upgrade building ratio and timing. There was this rule of thumb that you get one upgrade building (e.g., Engineering Bay) for upgrade for two base builds and two upgrade buildings for three base builds. Also, when you go for three base builds, you get the two upgrade buildings after you put down the third base. Building two Engineering Bay before you put down the third Command Centre actually works better with 2-1-1. The build gets two gas to tech up quickly for the two Medivacs, but there is no need for gas after that as you wanted to put down the third Command Centre and more Barracks. That means gas would bank up after the first pair of Medivacs. Thus, putting down the two Engineering Bay before the third Command Centre helps to spend the resource efficiently. This is so counter intuitive that people were arguing about what is the “normal” sequence.

Third, the build demonstrates the optimum building combination for a Stim timing, whereby just two Barracks (one Reactor and one Tech Lab) are sufficient. This knowledge has been applied to other match ups. For instance, in TvP, a popular variation was to get a Factory before the second Barracks and then move back to a 2-1-1 structure for the Stim timing. The Factory provides access to Cyclone and Widow Mine for early defense against Protoss. Without the knowledge of 2-1-1, players previously would simply put down two more Barracks without hitting a crisp Stim timing (i.e,. 3-1-0). Similarly, the 2-1-1 structure is also applied to fast three Command Centre in TvZ nowadays. The original 2-1-1 diverges away from the standard Reactor Hellion paradigm in TvZ, and these two builds were considered mutually exclusive. That is, if you open up with Reactor Hellion, you cannot do a 2-1-1 timing. However, as demonstrated by TY, the true value of 2-1-1 is not the sharp 5:00 timing but the optimum building combination for a Stim timing.

Three Barracks Reaper

ByuN was solely responsible for getting the Reaper nerf. Twice. Reaper’s KD8 Charge was nerf in patch 3.11 and 3.16. ByuN again created a TvZ build that does not use the standard Reactor Hellion. The build constructs three Barracks before expanding, and the goal is to deal damage and control the map with mass Reapers.

14 – Supply Depot
16 – Barracks
16 – Refinery
17 – Barracks
@100% first Barracks – Reaper and Orbital Command
20 – Barracks
@100% second Barracks – Supply Depot
Continuous Reaper production.
21 – Refinery
@100% Supply Depot – Supply Depot
@400 mineral (mineral will pile up as you make only Scvs and Reapers) – Command Centre

The build defied the “balance equation” that Reapers are only useful before Zergling speed kicks in. Without Zergling speed, Reapers can kite the Zerglings, so Reapers have an advantage over Zerglings. But with Zergling speed, Zerglings are fast enough to surround Reapers, and this “upgrade seesaw” is core to StarCraft balance. In Heart of the Swarm, Zergling speed usually is completed at 6:00 (old game clock), and Terran normally would pull their Reapers back to base in order to avoid losing them to Zerglings. The new KD8 Charge ability of Reaper in Legacy of the Void changes this upgrade interaction, because the “bounce” from the grenade can prevent the Zerglings from surrounding the Reapers (see vods above). This redefined the TvZ early game.

Engineering Bay block expand

ByuN brought something new to the table after he returned from his military service this year. He created a new opening that blocks Protoss’ natural expansion with an Engineering Bay.

Opening block

14 – Supply Depot
15 – Refinery, then send out a Scv
16 – Barracks
When Scv reaches Protoss’ natural – Engineering Bay block (don’t complete)
@100% Barracks – Marine and Orbital Command
@150 mineral – Factory
@100 mineral – Supply Depot
@100% Marine – Reactor
@400 mineral – Command Centre (account for mineral of the cancelled Engineering Bay; @100% – Orbital Command)

Build block

@100% Reactor – Put Factory on Reactor for 2x Hellion
@100 mineral – Supply Depot
@100% 2x Hellion – 2x Hellion
@150 mineral – Starport, then Refinery
@100% 2x Hellion – 2x Widow Mine
@100% 2x Widow Mine – 2x Widow Mine
@100% Starport – Medivac, then Tech Lab on Factory
@100% 2x Widow Mine – Put Barracks on Reactor and Factory on Tech Lab

The idea to block Protoss’ natural with an Engineering Bay is not new.  TY had brought this back to the spotlight recently. TY’s strategy emphasizes on using one base 1-1-1 builds to deal early damage. While ByuN’s strategy also stresses dealing early damage, it adopts a more economical approach by getting a Command Centre instead of a Starport after the Factory. This seemingly small difference challenges the conventional thinking that an Engineering Bay block would by default tech to Starport quickly on one base. The conventional opening would result in a quick tech versus fast expand match in the early game, but ByuN’s modified opening would play out as delayed expand versus delayed expand. I had written about this extensively here two months ago. Importantly, this is a new opening and not a new build (for reference), and it is extremely difficult to innovate a new opening. Other top Terran players have since adopted this opening into their arsenals.

I hope this article helps you to appreciate how ByuN’s builds challenge our understanding of the game. This is an underappreciated part of his legacy.

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2 thoughts on “ByuN’s Revolutionary Builds

  1. you understand that this build is completely fking garbage for anyone other than byun due to the micro and multitasking intensity it requires right? btw love the blog, keep up the good work.

  2. The reaper is definitely a ByuN build, but I feel like the engi bay block is actually insanely good in elemental leagues. Not micro intensive and pretty easy to execute while throwing a small spanner that can have big effects if not dealt with in a timely fashion.

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