1) What's the fuss?
Pretty much any toss has been in this situation - you are an average macro-PvT-focused protoss aiming to get an economical and unit count edge over the terran, then go air tech and pwn him. You do good, but every once in a while you meet a terran with good macro and a sense of timing and this is what happens: you feel totally helpless. Despite having a unit advantage at times, you have the feeling protoss units are totally inefficient and you always lose to that timing push, no matter if it occurs early in the midgame (4 factories) or later after the terran turtles and you're about to start air tech (6-8 facts and armories). Despite PvT being considered easy, you're being faced with a fact - A-move doesn't work. If that's the case, you're probably the one I'm writing this guide for.
2) Unit roles in protoss and terran armies.
Basically, everyone knows a terran's army consists of tanks and vultures and a protoss one of dragoons and zealots. There could be tweaks like an occasional reaver or high/dark templar on the protoss side or some marines/early goliaths on the terran's, but those are additions, the army bulks should be the ones listed above. Let's try understanding why it is so.
2.1) Unit counters.
Well, it's widely considered that there is a counter square: vultures counter zealots, zealots counter tanks, tanks counter dragoons, dragoons counter vultures. While it can work to some extent, it is in fact inaccurate. There are only two somewhat legitimate concepts here: dragoons are indeed strong vs vultures and vults are indeed strong vs zealots. However, to break pushes well, you must better realize how unit A works versus unit B. First of all, dragoons are not a pushover vs tanks. In fact, they are very effective versus tanks. They cost significantly less, they do about the same damage per second (basically, the damage per second of an unsieged tank and a dragoon are really close, with the tank being slightly ahead with 30/37, and the dragoon slightly behind with 20/30) and have more life, they regenerate shields quite fast (and that is quite important early-game), the only fields where tanks decisevely beat them are splash, range and projectile speed. This way, if you somehow manage to distract the tank fire from dragoons while you close in and keep goons spread, you will remain effective. This is the reason while people always start out with dragoons PvT - there isn't really a strong counter to dragoons at the point of the game where numbers are scarce and you can afford to micro hardcore. Thus, point number one: goons are universally effective.
Concerning the other counter pair - zealots and tanks, tanks follow a critical mass pattern. At first, they are indeed ineffective vs speedlots, but as their number increases, they start beating them unsieged, and if their numbers increase even more, they can afford the luxury to fight the zealots sieged. The reasons are simple - while tanks seem to do less damage to zealots (a direct tank hit kills a zealot in 4 iterations, a dragoon in 3, no matter the upgrades), zealots are usually very clumped, therefore, they receive an insane amount of splash damage and die to the tanks even faster than goons. Therefore, just running them in and a-moving won't do the trick. Zealots are very effective, however, if you somehow instantly get them close to the tanks and abuse friendly fire damage. Point number 2: zealot effectiveness vs tanks is limited.
Another counter pair would be vulture vs dragoon. Some facts worth noting: vultures do full damage to shields and shields compose almost half of goon life. Shooting goons with vults is not that a bad idea. Fact #2: vulture dies to 6 goon hits, tank dies to 8. But a vulture costs 75 minerals whereas a tank costs 150/100. Thus, despite the dragoon seemingly being a direct counter to vultures, it is actually profitable for a terran to make toss shoot at them. Point number 3: vultures are countered by dragoons in terms of direct confrontation, but vults are very effective at soaking up goon fire in a real battle. Plus, they get mines.
2.2) So, we've seen that both armies get the maximum of their effectiveness when mixed. But the reason of that mix is not the direct unit counters. You'd want to have a mixed army regardless of whether terran's army is balanced or is pure tank. Likewise, a terran would want to have a mixed army regardless of whether toss has zeal/goon, pure goon or pure zeal. It's very important to understand that. Mixing is good.
3) Generic push theory
A good terran push composition involves a tank line in the rear, a vult line in the middle (it's the mobile line which adapts to being in front of the tank line no matter what direction toss forces come from) and a mine line in the front. A good terran will remove all mines in the rear of the push because they do more havoc than good and will lay mines during the fight. How does it work? The mine line is essential - it protects the push from a toss army just walking into it. Toss has to defuse the mine line first or risk losing a large portion of his army. Mine dragging is good, but it doesn't really work if the terran has good positioning/controls his vultures well and you can't really expect to drag mines all the way to the tanks. However, it's ok to start running in with your zealots when mine numbers have been thinned, just don't fire prematurely. Tank line does the main damage and it's immobile, so it's function should be pretty clear. There are good and bad tank line shapes, but this is one of the pretty adavanced concepts that are hard to perfectly understand. Generally, it shouldn't be too clumped and it shouldn't be too widespread. Exact formations will not be covered in this guide. The vulture line's function is the most dynamic of all. First of all, obvioulsy, vults deal damage to zealots. Second, they can wear down goons by shooting at their shields, but this should really be only done if there isn't anything better to do. Third, vults act as a meatshield for tanks - they provide a direct physical obstacle in the way of toss army, making toss units take longer routes and clump even more so that they are vulnerable to splash. Fourth, vults soak up dragoon fire as mentioned above. Fifth, vultures can lay mines during the fight which is also an essential moment that makes pushes much harder to break.
So, these are the basics of how a push works. Now to discuss on how to beat it.
4) Engaging the push - army composition
That's it. Usually, before you get a first group of dragoons full, you shouldn't even consider zealots - dragoons should do just fine. Range upgrade is critical here, though, so if you plan to engage with the main terran force, do it asap. When to get zealots is somewhat dependant on style - some people costruct a citadel and produce zealots en masse after getting those first 12 goons, some people can get up to 2 full goon groups before getting zealot speed. A shuttle with 4 zeals is enough to bolster 12 goons usually, you start really needing zealots later. Note that a shuttle effectively increases your zealot numbers because they don't thin during approaching the tanks. So, 4 slow zeals in a shuttle could be somewhat close in effectiveness to 8 speed zealots without a shuttle, they just get into their right place in the tank line instantly. Zealot bombs are somewhat of another trick, though, dropping into the vult line can be even more profitable in that case, whereas during push breaking you almost always drop into the tank line. After getting 20 or so goons you should really invest into zealots though and from then one keep the army balanced. Note that when you are preparing to engage, queue up zealots in your gates - they tend to die first, so if you have to withdraw, you're going to balance your army sooner than if you ordered goons.
EDIT #1: When first writing this, I've forgotten to add one essential pre-battle trick that I had in mind. Always, I repeat, always designate goons and zealots to different control groups. They behave so differently in battle that you would never want to have them selected at the same time.
5) Engaging the push - micro techniques
5.1) Flanking.
This technique is extremely effective and you should make a habit of always using it no matter what unit numbers you have - for example, you have a terran army at point B and your army at point A1.
A2.......
........B
A1.......
Now, you don't just A-move your army to B, but first order in to move to A2. While moving, your army formation changes from a blob to something more resembling a line. Then, before your troops reach the destination, A-move dragoons to B. The difference is tremendous.
5.2) Defusing the mine line.
It is important not to run your zealots into the mine line. Most of the time you want the dragoons to take the first tank volley and only send the zealots after it. As mentioned above, zealots are very vulnerable to splash, be it mines or tank fire, so you want them to evade it for as long as possible. If the mine line is thick, consider attacking from a different direction, waiting for the terran to push closer or prepare for casualties. If a mine line is thin, you should engage in the following way - flanked dragoons take the first tank volley and send projectiles to the mines, then at the same time you send out your zealots. If everything is done correctly, by the time they reach the mine line, it's already largely defused and the second tank volley should strike them slightly later. Getting the timing right here can be very hard and it only improves with training. If the vults are positioned in the mine line, though, proceed engaging with zealots - goons will not defuse the mines that well, but the gross splash vultures take will compensate for that somewhat.
5.3) Diffuse micro.
This is another essential technique you should use every time - zealots are most effective when they are in the tank line. So you shouldn't just A-move zealots into the push, instead, you move the zealots in the tank line (effectively "diffusing" into the push), the press A-move once they reach it. It is probably one of the most effective things to do and it's relatively easy, so do it every time no matter what.
5.4) Goon micro.
There's a mistake many tosses do - they engage right, they diffuse their zealots and they just start watching the fight like if it was a movie of sorts. Then they come to the situation where their zealots are dying and their goons keep shooting vultures taking heavy tank fire. This is very wrong. Dragoons shooting at vultures are very inefficient so you should target tanks whenever possible. After your zealots are diffused, keep doing move and shoot micro with your goons trying to focus fire on tanks and getting closer after each shot. This can get very hard with large army numbers but it's still very effective. Such micro is countered by the terran by laying mines during the fight, so keep a close look at them - you'd want to home them into tanks whenever possible and avoid getting goon clumps hit by them. If you're being confronted with tanks only, you're doing fine. Your zealots should be ok fighting on their own at that time, so focus your attention on goons. On timings, it's good to move in with goons right after the diffusion because the tanks will get distracted and will fire at zealots allowing you to take a good position. Moving in sooner or later than that is generally a bad idea.
5.5) Shuttles.
In theory, it's very simple. You'd want to unload your shuttles either simultaneously with zealot diffusion or slightly before it to distract tank fire from clumped diffused zealots to lone unloaded ones, effectively lowering splash damage. But getting it done can be hard because those 2-3 seconds can get pretty micro-heavy. Practice, though, and you'll eventually get it right.
6) Conclusion.
As you can see, fighting with toss army may be easy, but getting the maximum out of it is probably just as hard as getting the maximum out of a terran army. There are lots of stuff to do, but the techniques described above could be VERY effective. For comparison purposes, I've setup an imaginary terran push in a UMS map that consisted of 16 vultures, 16 mines and 8 tanks. The toss force consisted of 12 zealots, 12 goons, 1 observer and 1 shuttle. The simulation was far from perfect as the terran didn't micro, but A-moving into that push resulted in a loss with like 1/3 of terran army alive (including half the tanks), while applying all of those techiques ensured a confident vistory with about 1/3 of toss army kept alive. As you can see, the difference is game-deciding. I've intentionally left out additional techiniques like shuttling reavers (can get really hard with unload timings, but potentially cruelly effective), DT's (very terran-dependent) and HT's (reach style push pwnage, again, very effective, but really hard to time right). This is a basic guide and I hope you'll find it useful.
EDIT #2: Also a part of the conclusion, as you can see, microing your army can get pretty intense and very deciding, but this kind of micro is very reliant on careful timing in a timespan of like 3-6 seconds. To be successful with breaking pushes, you'd ultimately want to control the position of every single unit and time everything with millisecond-precision. Sadly, that is not possible. You can try and bend the odds to your favor (and this guide focuses on how to do that), but still the results you're going to see will be pretty random. Better, but not always best. So, PvT is indeed a macro match-up in terms of that you would want to have a decisive unit count advantage whenever possible. Breaking a terran push with equal forces means taking risks, but it's still helluva fun.
Appendix A: Using Reavers.
Note: this part of the guide won't focus on reaver harassment tactics in general, but instead on using reavers to complement your army when fighting terran pushes.
1) The Protoss Reaver.
Reaver is a very potent unit. It can do enormous damage at the same time hiding safely in a shuttle. It's best matched against workers, but can be a feared tank killer as well. Utilizing it well can make your reaver build work vs almost anything terran can do, be it 2 fac, FD or plain fast expand build. The only terran build that does well vs reavers is fact port with a wraith or vulture drop (unless you do something crazy, terran's drop will simply come faster), but you don't see much of those nowadays. However, it's abit tricky in usage. I'll try to explain some aspects of how it works here.
2) Basic micro technique.
It's very simple on paper - you unload your reaver, right click your target, then right after firing you pick it up. However, it can get somewhat tricky because if you want to remain effective, you need to select your reaver at some time and spam 'R'. The way I do it:
- Select shuttle (hotkey 3)
- Wireframe drop reaver (a good habit, because often you will have other units inside your shuttle)
- Select both reaver and shuttle
- Right click target (unless it's a turret, in that case you need only reaver selected)
- Hotkey select shuttle
- Move shuttle about half screen behind the reaver (if you move it closer, the shuttle will have less acceleration)
- Select reaver
- Spam 'R' to build scarabs
- Right click the shuttle as it flies by
It can be done in an easier way - you generally don't need maximum shuttle acceleration vs terran, so steps 3 and 6 can be simplified. You can also load the reaver using the shuttle and right clicking the reaver - it again offers less shuttle mobility, but you generally don't need it vs terran. Now that the basics have been laid down, let's see how to get the most out of your reaver.
3) Solo shuttle.
This means your army stands near the terran push setup and waits. It is important, however, for it to be near, because solo shuttle is countered by terran by simply unseiging (turrets work, but to a much lesser extent), but him unseiging is precisely what you want him to do. If he tries this stunt, just engage with your main force. The exact technique stands as following - you load a shuttle with a reaver and two zealots, then first unload a zealot. What happens next - the tanks fire, your zealot dies and at the same time you unload your reaver, pick a target, fire and load into the shuttle. If you do it well, the tanks won't fire their second volley. Finish off your target by repeating the process. However, as simple as it may be, there are several tricky moments here.
3.1) Turret rotation - technique tweak.
Bearly all units in starcraft have a rotation time. This means that a tank that is facing a different direction than the one you unload at will fire slightly later than the tank facing it directly. The time gap is very small, much less than a second on fastest, but it is there. This can mean that vs 4 tanks, for example, your zealot might not yet be dead by the time you unload your reaver, and your reaver might get hit by the blast right after unloading. So make a habit of unloading on the move, so that the zealot and the reaver unload at different places.
3.2) Turret rotation - large tank numbers.
This becomes an even more dangerous issue when tank numbers are greater. Basically, what happens - the tanks facing the zealot fire, kill it, and the tanks facing the opposite direction don't fire at all. In a setup like this:
you will lose your reaver. Reaver usage requires a keen eye above everything. This is however not 100% accurate as there's a delay on "tank fires - unit takes damage" as well, so those rear tanks might still fire. But they as well might not, so you'd better not take risks with such an expensive unit.
3.3) Watch out for mines.
I rarely even consider reaver push stopping stunts when I don't have observers around unless I'm totally positive there are no mines. There are too many ways to screw up - your zealot might trigger the mines on the reaver, your reaver might trigger mines and even if you defuse the mines by pickup micro, you've still wasted a zealot.
3.4) Maximizing the damage.
Well, to the interesting part. Let us look at how scarabs traverse terrain. When having target set, they treat other units and buildings as obstacles and behave exactly like a melee unit when trying to reach their target. When a scarab comes in close vicinity to the target, it exlodes, dealing AoE. Let's look at the screenshot:
As we can see, there are three tanks, A and B are potential drop zones. Where you drop your reavers and what units you target can be a deciding factor on the damage you do.
Firing from A at tank 1 will result in the scarab exploding at x1, dealing a mere 100 damage to one tank. Not the maximum efficiency.
Firing from A at tank 3 may be a better choice, but it will most likely explode at x5, only dealing lowered splash damage (rr even no damage) to tank 1 and no damage to tank 2 at all.
A - tank 2 would be the perfect choice because it would most likely explode at x3, dealing full damage to all three tanks.
Now if you unload at B, firing at tank 1 will land at x2 (100 damage), at tank 2 - at x4 (100-150 damage) and at tank 3 - x3 (300 damage). As you can see, this stuff is important.
Generally, if several units are adjacent, you'd want to launch the scarab in such a way that it slides on the edge of a unit while reaching another one, described on the picture below:
Red line marks scarab trajectory, yellow arrow - the tank you want to target.
Firing like that ensures that you do full splash damage and maximize your reaver usage.
There's also nothing wrong in firing vulture clumps, a push without vultures is helpless.
4) Head-on assault.
Basically, the amount of different situations here is unbelievably large, at it seems impossible to cover them all. You should however, take notice that most of the tricks applicable when soloing are applicable here, so don't drop until you're totally sure that all the tanks have fired. If you catch the terran off-guard and he doesn't micro, this is basically autowin, but if he switches targets from your incoming force to your reaver, you might get screwed. The main difference from soloing here is that you may keep your reaver on the ground sometimies and that you don't need to fire it at the same targets. If you can do gross splash to a different unit cluster that you've fired first, do it, 50 hp tanks are a pushover anyway. If the push is small, you can synchronize your main force with the reaver, only unloading after a tank volley. There are two main techniques here:
4.1) Rear drop.
Your army shouts warcries and runs into the terran push, while your reaver is being dropped on the edge of it's firing range in your rear. This is applicable with large tank numbers or a widespread push when you're able to monitor which tanks in the frontline have made their shot and can launch scarabs safely. The terran's rear will be unable to reach the reaver. It's effective, but your attention will be focused on the reaver and it will be hard to micro the rest of your army. It's also the perfect position to fight unsieged terran armies. Yet your target selection will be limited that way.
4.2) Front drop.
This involves using reavers as the spearhead of your army. Basically, you load your shuttle with a reaver and two zealots (the unit that loads last will unload first so make sure that unit is NOT the reaver) and micro like you would normally micro a zealot-full shuttle - first set a direction for it, then press 'U' and click on the shuttle itself, so it unloads "on the fly". If you're proficient with it, your reaver will unload right at the spot you need it at. Then, select the reaver and fire at the most delicious target (usually it's the one nearing you). Proceed microing the rest of your army. This technique is best used for small or clumped pushes so that you're able to avoid most of the damage by just dropping your reaver next to the tanks. However, if you timed it right, you will still be able to make at least one shot, so feel free to use it vs pushes of any kind. Remember that with reavers time and space are linked - be careful not to drop it in range of misplaced tanks that can't reach the other units.
4.3) Multiple reaver dropping.
Well, this is a terra nova for most tosses and it's quite hard to theorize here. The only point worth mentioning here is that designating a specialized shuttle for each reaver seems safer than loading two reavers in one. You can make the same front drops with 2 or even more shuttles, but with that many, it could become next to impossible to monitor and control their safety.
5) Appendix conclusion.
Reavers are potentially devastating, but they are quite hard to use and somewhat unpredictable both due to scarab pathing and due to micro requirements. So, just going reavers to counter pushes is rather uneconomical. If you manage to use them for both offense and harass, you can win the game with reavers alone.