So I want to start by outlining a number of presuppositions that I take to be true in this matchup. These aren't all meant to be revelations; some of them are pretty obvious, but they're intended to explain why the matchup is the way it is - and where we might have gotten it wrong. I wanted to be rigorous about these so that if anyone views them as incorrect, they can be called out easily, and have it be clear where the disagreement lies.
Forge fast expand is the best Protoss opener in the matchup. Six months to a year ago, Protoss had not figured out how to deal with one or low-eco-two-base aggression from Zerg designed to counter the FFE: Roach-ling attacks, baneling busts, 6-pools, etc. Thus, in an attempt to play safe against these attacks, many Protoss used gate-first openings instead of the FFE. Now, however, it has been demonstrated that a FFE build, competently executed and with sufficient scouting, can fend any of these attacks and come out ahead. Therefore, the FFE dominates all other Protoss openings.
Once the FFE is scouted, the Zerg's options are to go for two or three base play. One-hatch aggression, as I mentioned, is not a strong option against the FFE. Also, between the FFE cannon walloff and sentries, there is nothing that the Zerg can produce on tier 1 that can cost-efficiently attack into the Protoss. Thus, the options are to either go for some Lair tech on two bases, or to try to outmatch the Protoss economically with a three hatchery style.
Conventional two-base Zerg aggression looks increasingly obsolete. When the matchup was in its nascent stage, a number of Lair-based 2-hatch styles developed to put the game in the Zerg's ballpark. These included Nydus Hydralisks, Hydra creep pushes with overlords, 2-hatch Muta, and ling-infestor timing attacks. These pushes have all but vanished from both the ladder and progaming scene, for the simple reason that they didn't turn out to be very good pushes. They weren't hitting the right timings, and weren't nearly as hard to defend as the equivalent Protoss 2-base all-in.
Therefore, three-hatch play has become the default response to an FFE in ZvP. Since it looks like the Zerg can't effectively punish the Protoss on either one or two bases, three-hatch play looks like the best way to go. The Zerg's gameplan is now to play reactively, eco up to 60 drones or more while getting Lair tech, and fend any aggression using Roaches and Zerglings, eventually transitioning to higher tech.
3-hatch Zerg openings are very good at denying an early third from the Protoss. The aggressive build pioneered by Stephano - the 12-mintue Roach max - is extremely effective at punishing (or outright killing) a Protoss that attempts to continue to play economically off of their FFE by grabbing an early third. Many Protoss feel that they are incapable of defending a third Nexus against the sheer quantity of Roaches the Zerg is capable of producing off of three bases. That's not to say that there aren't any builds in the metagame capable of securing a quick Protoss third, but they are sufficiently difficult to execute such that they are not the norm.
Therefore, Protoss tend toward attacks off of two bases that hit before the 3-hatch Zerg can get aggressive. This is the face of the current ZvP metagame - 2-base Protoss timing attacks against 3-hatch Zerg defense - and it's not one that everyone is terribly happy about. It's not that taking a third against Z is impossible, but it is quite hard to do safely unless you get aggressive first and put the game in your ballpark.
The current Zerg style of playing against these attacks is a razor-thin defense. Typically, the Zerg will scout the Protoss's tech in the main and gases at the natural between 6:30 and 7:15. This will inform how many drones they're allowed to produce from that point onward. As a rule of thumb, it's generally around 60 - more if the Protoss is going for a 4-gas tech-heavy attack, less if they're going for a 2-gas all-in gateway attack. Regardless, the modus operandi is to produce as many drones as possible and only start producing units right before the attack hits.
These attacks are difficult for the Zerg to defend with their current playstyle. There are a number of reasons for this. First, the suite of attacks that the Protoss can choose from is diverse enough that it is sometimes difficult to scout and react accordingly. There are a huge number of variations, listed in order of perceived popularity:
* Immortal/sentry timing attacks
* 7-gate +2 blink stalker timings, with or without warp prisms
* 6, 7, or 8 gateway timings, with or without warp prisms
* Sentry/warp prism attacks that force field the Zerg's ramp
* Mixed gateway/stargate attacks
* Double stargate all-ins
* Colossus timing attacks
all of which can spiral out of control if not reacted to correctly. These attacks are also varying degrees of all-in. A cutthroat 6-gate that stops below 40 probes is certainly all-in, but a Protoss that continues to build probes and does a delayed timing with immortals and sentries can still viably secure a third, either before or after the push. Therefore, even if their push doesn't outright kill the Zerg, the Protoss can frequently transition to the next phase of the game without falling behind.
The goal of the Zerg in this situation is to defend the push with a higher drone count and end up ahead. From there, they can start building infestors, mutalisks and/or hive tech, and break the Protoss with superior economy and tech. Which brings us to the last and possibly most contentious point...
This may be the ostensible goal of the Zerg, but it isn't happening often enough. If we examine what these defenses tend to look like, both on the ladder and at the pro level, they don't often look like a game state that I want to play for deliberately. Drones are pulled, hatcheries are lost, spine crawlers are thrown up panickedly between warp-in cycles, queens die left and right. Even at the highest level of play, Zerg are sometimes just stomped by a two-base all-in without being able to put up much resistance. And even if the push is eventually fended, it's often done so at such a high cost in lost drones and hatcheries that the Zerg has not achieved his goal of coming out ahead by defending.
I understand that this last point is something that, if one were to disagree with it, could only be settled by looking at a ton of different replays - something I don't have the time or inclination to do right now. If your experience on the effectivenss of Zerg defenses in ZvP differs, then there's not much else to say. But this has, at least, been my experience both on the ladder and watching pro replays.
So where does that leave us?
It's my belief that the current Zerg style of opening three hatch and defending off of ~60 drones is wrong-headed. What I want to question is whether the assumption that the Zerg can take three hatcheries, drone to 60, get Lair and still fend all two-base attacks from the Protoss is dogmatic and greedy. It's been my experience that this form of opening is not robust enough at defending against Protoss aggression.
What is the alternative?
As I stated, I don't think that two-base aggression from the Zerg is an attractive alternative. It might catch an opponent off-guard in one set of a Bo3, but it isn't a place the metagame is going to stabilize at. However, there are a number of safer openers that I'd like to see players experiment with:
* Two base defense with an in-base macro hatch, taking your third after the push is defended
* Three hatch defense, stopping drones at or around 44 and massing speedlings in advance of the attack, droning to ~70 after the push is defended
Why are these openings more attractive?
First, let's talk about the drawback of these openings. In the hypothetical best case scenario of the three hatch 60 drone opener, if you defend without losing drones or hatcheries, you will end up more ahead than you do if you defend with either of these openings. This is to be expected; it's a greedier opener, if you get away with it you will be more ahead.
But how many more two-base attacks are you losing to by going for this opening? One thing I've noticed after defending many Protoss 2-base attacks is that they're extremely tempo oriented. The force they move out with initially is not that scary, but because of how many gateways they build it looks really daunting after the first warpin. However, because the Zerg is always trying to squeeze in as many drones as they can before the attack hits, they very rarely have the opportunity to attack that weak initial force.
Once the first warpin hits, the tempo is in the Protoss's favor. Even if the Zerg has a superior economy and is producing more total army value of units, the fact that the Protoss had more units at the start makes every phase of the engagement more cost-efficient for them. However, if that weak initial force is greeted by a huge mass of speedlings before the first warpin, this tempo shift never occurs. The attack is either crushed outright, or the Protoss cuts his losses and goes home. The two-base defense into third is particularly easy to defend, because you can spread creep further in one direction, and only need spine crawlers to cover one point on the map.
But will the Zerg really come out ahead in this scenario? They'll have so few drones!
That's what needs to be theorycrafted and tested in-game, but I think they might. Once the first timing of the Protoss is thwarted, the Zerg will have a considerable window to drone up and take their third if they haven't already. The large number of units they massed is also likely to be able to deny any third the Protoss tries to take. Thus, the goal of these openers is to
* take your economic lead after the first Protoss push, rather than before.
* structure your drone production the same way as other races - producing a mix of drones and units simultaneously, rather than operating bimodally (building all drones and then all units)
At the very least, I think this opener is more likely to defend 2-base all-ins. Where the matchup goes from there is an unexplored point in the metagame that is worthy of investigation.
Anyways - that's pretty much the gist of it. I don't have replays to share, as I don't think I'd be executing them at a high enough level for them to be persuasive. I just posted this because I think examining the logic and theory behind ZvP openers is pretty interesting. Thoughts?