TvP: Engineering Bay Block Expand Opening

ByuN played his first GSL game yesterday since his return from the military service. This post discusses the Engineering Bay block expand opening that he used multiple times against his Protoss opponents.

Build order

I am going to first list the build order of the main variation (see vods below).

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

Game plan

Based on the concept of build order blocks, I break the build order into the respective blocks for clarity. What caught my attention is the opening block. The main idea is to delay both players’ expansion by blocking with the Engineering Bay, while Terran tech up to Factory. If Terran were to tech up to Factory right after Barracks on one gas, mineral would bank up. The “leftover” mineral is not enough for a Command Centre, so you can either spend it on a Barracks or an Engineering Bay. The additional Barracks does not line up well with the intention of the build. The Engineering Bay on the other hand either delays the Nexus or forces Protoss to build it at another location. If Protoss builds the Nexus in another location, the area needed to cover against a tech based attack with an early Factory increases.

This idea is not new, and 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 (see vod below). 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.

For ByuN’s build, the first attack hits with four Hellions. For TY’s build, the first attack hits with a drop of three Hellions at a slightly later timing (it could be earlier if you proxy the Starport). If the Nexus is not placed at the natural location (e.g., third expansion location), the difference between the two attacks is relatively marginal. This is because Terran can simply run the Hellions into the main base without using the Medivac. However, if the Nexus is placed at the natural, then the attack with the Medivac would be better.

More importantly, ByuN’s much earlier Command Centre really sets his build apart from other Engineering Bay block comparisons. In a normal one Barracks/Gateway fast expand mirror situation, Terran’s Command Centre completes later than Protoss’ Nexus. The completion time difference in ByuN’s Command Centre and Protoss’ Nexus is comparable to what we would normally see when Protoss uses a Cybernetics Core before Nexus opening. In other words, while ByuN’s opening looks aggressive and not economical, the Engineering Bay block attenuates the economical difference of the openings. This build essentially reaches the typical 1-1-1 on two bases convergent point with a twist to get an earlier Factory.

Variation and transition

ByuN followed up with a Widow Mine drop. I believe this is optional, as you can do whatever you want with the 1-1-1 set up. My focus is on the opening itself, because I think it is paradigm shifting. You can use this opening for other builds. For example, in the vod below, ByuN did not swap the Factory onto the Reactor, and he produced Marines and a Cyclone. This makes sense as ByuN knew PartinG wall off the natural, so the Hellions would not deal damage.

Even if you follow up with ByuN’s choice of Widow Mine drop, you still have the flexibility of the 1-1-1 structures. He has the Barracks on the Reactor, the Factory on the Tech Lab, and the Starport with no add-on. This should be familiar to every Terran player. The Hellions run by and Widow Mine drop provides scouting information of Protoss’ tech choice, and you can then follow the standard framework and adapt accordingly:

  • Twilight Council -> Siege Tank and Raven (first vod below; timestamped, pay attention to production tab)
  • Stargate -> Cyclone and Viking (second vod below)

The opening I discussed thus far gets the first Refinery at 15 and tech up before expanding. In the two series ByuN played in GSL yesterday, he mixed in the Engineering Bay block with other orthodox openings. For example, in the vod below, he used a 16 Barracks 16 Refinery opening with Engineering Bay block, but he pulled Scvs off gas to get enough mineral for the Command Centre (trade off with Engineering Bay block).

Just a side note, at first I thought sending the Scv at 15 supply is too early, but you would have just enough mineral for the Engineering Bay when the Scv reaches Protoss’ natural. Also, by the time the Probe wants to build the Nexus (before Core), the Engineering Bay is already 50% done.

Shout out to Jonathon and Michael for their contribution to the site. Your support helps to sustain this site.

This article is translated and posted on scboy.com by 绝迹.


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9 thoughts on “TvP: Engineering Bay Block Expand Opening

  1. Translated:https://www.scboy.com/?thread-165262.htm#2547660
    Recently this build has gained great popularity and TY also mentioned in his stream that terrans will always get an advantage if the e-bay block goes successfully. Love to see how protoss players will counter this later on.

    1. Thanks for the translation. Yeah, I read that from TY’s youtube video. Someone mentioned about the position of the Engineering Bay (to avoid vision of scouting Probe). I had that in my note but I forgot to mention it haha.

    1. I think the biggest draw to the eBay block is that you limit options of P. This variant skips Reaper to get Fact up asap, so your scout is worse, but after block P either takes the 3rd position or does delayed natural with Core+Zealot. And your early Fact Hellion are good vs Adept pressure, you can get mines, tank, cyclone, etc.

      It seems to be similar to PvZ blocks, where P wants to force Z to be exposed to Adept timing harass and then counter Roach Z uses to beat adept with Sentry/Immortal. T doesn’t have such a radical plan about the unit comp. It rather tries to limit P money (gateway)access to then attack with T tech that is countered by gateway and not P tech.

      Considering the amount of 2:50 3cc we’ve seen before in all matchups from pro T, I’ve found this build very exciting, as it really spices up the recently stale matchup.

  2. I’ve been derping with the build since yesterday (5k MMR EU) and one thing I noticed is how well it counters proxy stargate builds. If you scout a pylon missing after sending the SCV building the EB into Toss’ main, you simply finish the EB, build turrets and build cyclone+double marine. I’ve won like 5 games already against the proxy SG.

  3. “If the Nexus is not placed at the natural location (…) Terran can simply run the Hellions into the main base without using the Medivac.”

    You can actually block the ramp with a pylon and a single stalker. In that case, an unnoticed drop would wreck the main.

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