[G] How to Improve

Your questions are good and I'm happy to see you are watching the games you have listed. It's not a problem that things don't make full sense right now, just keep asking questions and learning patterns and it will come. I could write for dozens of pages on this and still not be able to explain everything fully so I'll try to focus on a few key points.

A great deal of TvP comes down to information. Protoss have a technical map hack potential in the observer but it is something they must use and fight for, not be given. The Terran is the one who directs the flow of the match and the Protoss reacts, so if they are denied information, they will not know what to react to properly. Sometimes, getting the observers themselves opens them up to timing windows.

For example, the fact cc fact you mentioned. This build has several ways it can work, depending on how each side opened (fact cc/rax cc, 1 gate expand, 1 gate obs expand; doesn't apply if Protoss 12 Nex, 2 gate expand or later or does reaver/dt off 1 base). In each case the Protoss is sacrificing a 2nd gateway of dragoons in order to get something else (tech/nexus) and you will have a window for unit superiority. The fact that this exists (and it is probably the most popular strategy at the moment) hurts Protoss options as well; if they want their observers fast they have to take a major risk. If they want to avoid that risk (say 1 gate expand -> 2nd gate before robo), they are delaying their observers and making it harder to figure out what is going on.

The 2/1 timing attack variation is one of the most flexible (and therefore least allin strategies). If for example you do the Hiya build (fact cc cc armory -> mass fact timing attack) you are cutting upgrades and tech and expansions in order to deliver a powerful knockout blow. This makes your attack comparatively stronger, but if the Protoss can avoid critical damage, they will be way ahead. That is not the case for the 2/1 timing attack (assuming an even game up till that point), where you are not sacrificing anything, but more going a middle path. So long as you don't get routed you will still get a protected 4th base up, have excellent upgrades and tech, and still have map control potential. At the same time, you aren't going to win that battle and win the game right there nearly as easily.

A big part of it is also the complete immunity to 2 base tech builds. The fast armory/academy means that you will repel any 2 base reaver/dt (which are very good otherwise) with ease; this is what opens up the window for the 2/1 timing in the first place back when the strategy was created as the Protoss invested in an attack that can't do damage. If for example you would do the Hiya build mentioned above and gear towards the timing of the Protoss taking an overly fast 4th base (which they would like to against a 2/1 timing), a 2 base reaver or dt drop would likely do solid damage and be an effective deterrent to that timing push. But as a general rule of thumb, attack upgrades in TvP are game-changing. The 2/1 attack rushes that 2nd attack as fast as possible and gears the attack around the strongest a Terran army can be with it, regardless of the Protoss actions.

Now why can't the Protoss just optimize, take 3 bases really fast, get some gates/tech and take a 4th? They don't know what the Terran is doing. If they want to take a risk they can go arbiters and take a 3rd base off 2 gate (dies to oov build/fact cc fact), or do 1 gate double expand (dies to same thing). If they don't want to take a risk they might 2 gate obs nexus and have defending chances vs oov build and repel a fact cc fact, but be weaker against a 2/1 or Hiya build, and they will certainly be behind if the Terran takes a very fast 4th base.

A great example of the information problem is in Bisu vs Flash on Medusa here. Flash goes fact cc armory cc and repels Bisu's early pressure (tiny lead). The key point is Flash's turrets prevented Bisu from knowing what he was doing, forcing Bisu to make some assumptions. I'm not quite sure what Bisu though he would do (I'm guessing 2/1 timing attack) but Bisu was certainly confused when he saw Flash take his 4th before attacking (Flash did it off of 2 factories!!). Had Bisu gotten the key information of factory and troop count he would have crushed Flash's middle position and had a winning advantage (he had 200 supply to 120).

But he didn't know, and this lack of information made him hesitant. Instead of either attacking or expanding fast to 3, he held on 4 bases in order to mass up and prevent an attack (that didn't come!). When he thought Flash was turtling instead of attacking when he needed to, he made a recall that was a minute or two late. Instead of Bisu killing an expo and eventually stalling Flash's attack (which would have happened if Flash had taken his 4th later in the same continuation), Flash has enough income and army to dominate the key Protoss natural choke, repel the recall and reinforce, and therefore win the game.

As for Stork/Flash on Tau, make sure you assess the whole game. Flash is able to do damage with a fact cc fact and gain an advantage while Stork gets 2 base reaver and does little. This advantage lets Flash continue to expand rapid to 4 bases while getting upgrades and tech and keep up the harass (Stork can't attack the fast exapnsions or he dies to harass, he can't defend from harass fully due to lack of units/money for cannons). Flash keeps up his harass for as long as feasible and he has a really flexible window of when to move out given his large advantage. He just needs to attack before Stork can recover from all the harass.

For Flash/Shuttle on RotK, Shuttle goes 1 gate obs nexus -> 2 base reaver Nexus. The fast observer lets him confirm Flash's intentions at least for the start (to go for 3 base with armory, but he can't know if he goes for 2/1 timing or fast 4th) and he is economically behind. Flash's drop does no damage, so the game is pretty equal at that point. The problem comes in that Flash goes for a 2/1 timing but he doesn't actually make the attack, possibly sensing that it wouldn't work well due to his failed drop and Shuttle's expansion timing (I'm not quite sure). So Flash takes his 4th at 2/1 timing (he could've taken it much faster and been ahead) and the position isn't looking good for him. His harass does slow Shuttle down a bit in taking more expansions (ideally he would've wanted all the bases at 11 up sooner) but Flash's decision making wasn't the best this game or this series (he screwed up and lost the first game too).

Now the game turns more into a contest of maneuvering. Flash either needs to fight a battle at a vastly superior position and win decisively (as Shuttle simply has so many expansions), then rapidly kill of Shuttle's expansions and prevent him from amassing a new army, or he needs to slowly take the expansions at 1, establish an impregnable defensive position and simultaneously prevent Shuttle from doing so. This is why Flash is spending so much time with his vultures during this otherwise idle period, and why Shuttle is moving his army around constantly to stop the vultures. Note that Flash does not have to commit to either plan, he just has to execute one successfully. However, the 'win a big battle' plan needs to happen before Shuttle can establish a full second battery of gateways at 11 (which the harass did delay). Flash's best hope is that Shuttle screwed up and maxed too quickly with only one arbiter (though he has templars).

The key point comes when Flash lures Shuttles army away from the middle into clearing mines at the mid right and then into 1 (Shuttle can't get observers in position to see Flash's maneuvers due to goliaths + vessels and turrets). Flash quickly takes the high ground and mines up, putting himself at a massive advantage. Shuttle will die if he attacks the position from the single ramp, especially with the lack of stasis available. Shuttle's retreat path is very long and Flash can easily attack his natural or 11 expansions from a vastly superior position(countering is not an option due to the mines/terrain/central position superiority). His attack up the ramp was a bad one but it was a move of desperation; he could have made a fight had he retreated north and tried to await an opening.

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Original Message:
First off, I absolutely love the guide you wrote. It states with certainty many of the things that I have suspected since I started playing Broodwar. The list of VODs and advice on how to improve has so much common sense and sound reasoning behind it.

I'm a rather terrible Terran player with a short history in broodwar. I was looking through the builds you listed examples for, and it looks to me that two of them (FE into 2fact timing and 4fact) are designed to hit the protoss when he is either taking a third or I suppose teching too fast to arbiters. That's what I would summarize the overall 'goal' of the build as (correct me if I'm totally off).

However, I don't at all understand the 'goal' of the Flash build. The explanations I've read (not ideal, I guess) suggest that the build aims for a timing attack when you reach 2/1 upgrades. This does not make very much sense to me. Unless there's some direct consequence of these 2/1 upgrades that I am missing (like +1 zealot attacks in PvZ), isn't the idea of pushing out blindly at 2/1 well, rather foolish. Why shouldn't the protoss simply optimize his economy to have the maximum number of units when this push comes out? How can a 'timing attack' not be based on how the Protoss is spending his money?

I went to liquipedia, and while it informs me that 2/1 is merely a guideline, and that terrans should push to take advantage of a protoss expansion to teching to Arbiters/Carriers. While this makes more sense, I have a hard time ... well, believing it. I can see how 400 minerals might be a major concern in the early game (explaining why the 4fact and CC into 2fact timing builds work). However, in armies that are presumably 150 food, can 3 dragoons really make such a big difference?

I also tend to have a hard time understanding why Flash pushes when he does. In some games, like Flash vs Sangho on Medusa, its seems to be rather obvious. However, in other games such as Flash vs Shuttle on ROTK and Flash vs Stork on Tau Cross, I really have no idea. At best what I can think of is that Flash pushed relatively soon after Shuttle's first arbiter was out in his game on ROTK. What kind of timing is that hoping to exploit? Shuttle has already spent on the Stargate and Arbiter Tribunal, so while he might be short that many units minus the gateway cost, he's already reaped the benefits of his investment, hasn't he? Or is there some critical mass of Arbiters that makes the army that much more effective?

I guess in more general terms, there's something I must be missing about the concept of a timing attack. Like I said, I can sort of grasp the idea of pushing based on tech: a Terran pushing out with 3 tanks to exploit the lack of defilers and pressure the Zerg front, a +1 zealot attack in PvZ, etc. It seems to me that these attacks have less to do with where money is being spent and more to do with ... unit counters, for lack of a better term. However, pushing out against a maxed protoss because he spent 400 minerals - none of which could actually go into army production because of the supply cap anyway - seems questionable. Is that actually the reasoning?

I appreciate any response you might have to my overly simplistic and probably rather foolish questions =)