Strategy Tutorial: Zerg Early Game explained - 9 Pool, 12 Hatch, Overpool & all

This post will attempt to clarify certain aspects of common Starcraft language that is anything but self-explanatory and confusing for newcomers to understand. You may have heard about ‘4-5 Pools’, ‘9 Pools’, ‘Over-Pools’, ‘12 Pools’ and ‘12 Hatch’ – here it will all be explained.

Essentially, it all comes down to when and in which order to build Your Spawning Pool and second Hatchery – that is the Zerg player’s early game. Over the years, set theories have been developed in order to perform optimally against certain threats and to achieve predetermined goals. A 9 Pool opening strategy will give benefits and disadvantages that greatly differ from, say, a 12 Hatch strategy.

The numbers referred to in the name of these build orders refer to the supply count, or ‘food’, by which you perform a certain action. A ‘9 Pool’ means that You build the Spawning Pool when the supply is at 9 – i.e. with Your ninth drone, since that’s the only unit beside Overlords You have at stage in the game. Conversely, a ‘12 Hatch’ dictates that You construct the second Hatchery when You have reached 12 supply.

The basic idea is very simple: Spawning Pool first means that You get a strong early army, but not with the fast economic increase generated by getting Your new Hatchery first. There are trade-offs, pros and cons, hybrids of the two and many variations. See below for the most common ‘core opening’ Zerg build orders:

4-5 Pool:

These build orders are designed to give You 6 (non-upgraded) Zerglings incredibly fast so that You can bring a very early rush to the opponent – either securing You an immediate win or a sure loss. Because, if the rush fails, You will have sacrificed all ways of competing economically with the enemy, and You have very little chance of winning. Hence, this is what’s called an ‘all-in’ strategy – it’s do or die.

Detailed build order instructions, courtesy of Liquipedia:

5 Pool vs Protoss

5 Pool vs Terran

9 Pool & 9 Pool Speed

This strategy can, depending on Your strategic choice, be adapted to use speed upgraded Zerglings (requiring 100 gas that You otherwise would not get that early) or normal ones. It is a build order that enables early aggression, as opposed to getting an early economic lead, but it is not an ‘all-in’ move – You are still able to transition into a longer and economically stable game. With a 9 Pool You can with your early Zerglings fend off scouting units and early rushes from the enemy.

In essence, this tactic with its variations are designed to apply pressure to the opponent and thereby giving You the opportunity to expand. It is also a strong choice in warding off early aggression from the enemy – meaning that You are either able to pin him or her back while You build Your economy or that You can face any incoming threats with force. ‘Aggressive yet safe’ is the common description.

However, though the basics are the same, the way You perform and utilize any type of opening strategy depends on the race of the opponent. Against a Protoss who Fast Expands, a 9 Pool build can be most effective: potentially overrunning the expansion (unlikely against beyond average players) but at the very least force the Protoss player to put up defenses, i.e. fast Cannons and blocking Probes. That decreases the economic benefit that the Fast Expansion is supposed to generate, which early in the game can give the Zerg player a vast advantage.

A Terran player has different defensive capabilities to a Protoss, and is more or less open to harassment (attacks that are not meant to end the game, but to delay and make life difficult) until the point where he or she reaches Academy tech. Then the Marines and Medics will be able to push Zerg back and comfortably seize their own Natural Expansion. An aggressive 9 Pool strategy can be used in order to deal enough early damage before this happens to leave the Terran at a disadvantage, given the pressure that can be applied by lots of quick Zerglings before the Academy is ready.

Zerg vs Zerg is an entirely different matter indeed, and will be dealt with in a post of its own.

Based on the 9 Pool opening, You as a Zerg player have a lot of strategic options to transition into. It is a very unlimited build order, geared towards enabling any type of of more advanced strategy that the Zerg has in its arsenal. Depending on the game and Your opponent’s choices, You are well equipped to respond with any type of unit and army composition.

Turning to the best in the industry, the staff at Liquipedia provide all the details we need to properly execute all the variations of the 9 Pool – with suggested follow-up strategies:

9 Pool vs Protoss

9 Pool vs Terran

9 Pool SPEED vs Protoss

Overpool

This is the Overlord-then-Spawning Pool variant of the standard 9 Pool build order. As the name implies, it means that You build Your first Overlord (not counting the one that’s included when the game starts) before the Spawning Pool. In essence, this is used as a more economic (and hence less aggressive) opening build order – as You get Zerglings later but slightly more minerals.

This method is generally seen as more defensive than the standard 9 Pool, the first Zerglings are there to prevent early incoming attacks or non-standard rushes (so called ‘cheese’) – but it can be adapted in a number of ways to deal active damage. Depending on the timing of the fast expanding Protoss, You can use this build to quickly acquire 100 gas (the amount necessary for the Zergling Speed upgrade) and with 12 Zerglings overrun the defenses at the expansion.

That only works if You have sufficient scouting information and can judge the timing correctly, and it means that You devote the economic advantage (for which the strategy is designed) of the Overpool build order to an early attack with upgraded Zerglings. Starcraft is a game with very thin margins, and a match can be won or lost in two seconds. Key decisions and gut instincts combined are crucial.

Exact Overpool build order – economic and aggressive, at Liquipedia:

Overpool vs Protoss

12 Pool

Halfway in between the aggressive-yet-safe 9 Pool openings and the economically stable 12 Hatch strategies, we have the 12 Pool. Here, You construct an Overlord early (optimally at 9 supply), then additional Drones and then a Spawning Pool when You reach 12 supply. The second Hatchery will then follow once You have acquired 300 minerals – which will be sooner or later depending on if You choose to construct an Extractor to get early gas or not.

So what is this good for? Generally, the 12 Pool is said to be neither bad or good against anything – it is an average solution, neither overly aggressive or good for Your economy. However, there are situations where You will need Zerglings no earlier than 12 supply but no later either – in such cases, both 9 Pool and 12 Hatch openings are likely to lose You the game. The 12 Pool has its place.

Build Order, via Liquipedia:

12 Pool vs Protoss

12 Pool vs Terran

12 Hatch

Unlike the previously mentioned 9 Pool strategies, the 12 Hatch build order is designed with pure economics in mind. To clearify, the earlier You get a second Hatchery the sooner and faster Your intake of resources will increase. However, only building Hatcheries will leave You exposed to enemy attacks. The 9 Pool and Overpool strategies will give You early attacking units to use aggressively and defensively, but does in turn delay the construction of Your second Hatchery.

When performing a 12 Hatch build order, You construct the Hatchery before the Spawning Pool. That way You will be able to stay on even terms with a Protoss who performs the standard Fast Expansion strategy, and similary to a Terran that expands according to normal timing. If You manage to defend against early enemy aggression that attempts to exploit the weaknesses of this economic build order, You as a Zerg player are very well suited to transition into any type of late game strategy.

That is, of course, the theory. Only against players below Your own skill level will You be able to sneak by with a purely economic build order without getting severely pressured. The key is to get away with planting the Hatchery before the Spawning Pool (i.e. not being able to construct Zerglings until relatively late) without succumbing to early aggression. There are ways to achieve that.

You want to place Your second Hatchery at Your Natural Expansion (a feature that all professional Starcraft maps have, the game is built around that mechanic) and preferably place all Your defenses there to protect both Your bases. Before You have Zerglings, You will have to use Drones to fight incoming Protoss Zealots and Probes, and likewise against a Terran that rushes You with Marines and SCVs (who are likely to build offensive Bunkers at Your ‘front door’).

Constructing static defence, Sunken Colonies, may often be a necessity. This hurts Your economy, since You are sacrifing a Drone for each building, but if it keeps You alive until You can utilise the economic advantage then it is still a success. The key is never build more than what You have to – which You will be able to determine by knowledge of the opponent’s timing and Your own scouting information. Overlords placed on the right spots across the maps will tell You what iss coming, and enable You to prepare.

A 12 Hatch strategy puts You on the defensive in the early game, but gives You a stronger economic boost into the mid- and late game than the 9 Pool build orders. If You know Your opponent, the map and Your own preferred play style – You can choose the best opening for the occasion. Variation is essential, keep them guessing, but so is experimentation – these are good guidelines, but when You reach a certain level of skill it’s the deviations from the norm that win games.

How to 12 Hatch vs Protoss (Liquipedia):

How to 12 Hatch vs Terran

The differences between the openings depending on the opposing race are small, it’s the mode of later transition that varies greatly – and of which You need to have a clear plan. That will be dealt with further in coming articles – in this one the purpose has been to clearify what the differing Zerg opening strategies are called and what they are designed to do.

More strategic reading at Polygon reVue:

SK Terran – Playing Terran vs Zerg the Bionic Way

The Bisu Build – Putting the Protoss Fear into Zerg

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