What is it?
Well, the name is pretty self explanatory. The terran player opens with a basic medic marine build, and generally some timing push involving a vessel. After a while, the terran player stops making medic marine and transitions into a pure mech army with tanks and vultures and goliaths and mines. The game that started it all:
What's so good about it?
Well, this build has been giving Zerg headaches for a number of reasons. I'll list some of them:
1. Army composition.
This one is fairly simple: Terran dictates the army composition. Zerg doesn't go hydras because he wants to, and then forces Terran to switch from bio to mech. If terran goes bio, Zerg must go ling lurker. If terran goes mech, Zerg must go hydra muta. Switching to mech lets Terran rain chaos on Zerg's lurker ling. While a zerg can make the switch, he will usually have plenty of useless lurkers he has to suicide, and he won't have many upgrades (attack or speed or whatnot) for his hydras, which lets Terran establish further map control. Ultras? Well, unfortunately ultras aren't that great against mech, and they eat a lot mines. To paraphrase Day9: "Hydra muta is the optimal composition vs mech. I've always said Ultras let siege tanks maximize their damage".
Mutalisks are actually pretty good against mech. They hold their ground against goliaths, force Terran to make said goliaths (which then don't fare too well against hydras), and give Zerg a lot of opportunities to attack and counter attack. When a Terran goes mech, he usually won't tech to vessels for a while. Often times the terran even has to resort to valks to combat the threat. With the bio --> mech transition though, vessels are available and shortly become numerous, effectively shutting down mutas and allowing Terran to survive with very few goliaths: the rest become those pesky vultures.
This game is a fairly good illustration of this (and it's just a fantastic game). Note how quickly Jaedong's mutas get repelled around the middle of the game, even though Midas has like 4 goliaths in the game.
The mech transition usually happens when Zerg is playing lurker / ling / defiler and looking to establish his 4th base and ultras. It's obvious here why mines are good: they ANNIHILATE this composition. Defiler lurker pushes? ling lurker pushes? Anything involving zerglings and lurkers? Boom. Even when ultras come out these bastards are annoying. That's the most obvious reason mines are so awesome. The unit composition Zerg needs vs bio just sucks against them. Another reason though: since Zerg can arely attack until they get an adequate hydra force to take out the mines, Zergs find it very hard to use the timing window during which terran is switching composition. This is a pretty big deal.
The following game illustrates how awesome mines are, as well as how hard it is to deal with mech having to use the wrong composition. It also shows how the mines during the transition make it hard to Zerg to abuse the timing window.
I saved (in my opinion) the most important for last.
Straight up mech is a pretty outdated thing. Sure, it works on some maps but in general its fallen out of favor. Why? Because it offers Terran no map presence for a long time. 2 Base mech timing pushes are fairly easy to delay and hold off. Mech allows Zerg to get their 3rd up almost uncontested, and drone whore / expand a lot more after that too. Jaedong illustrates the most extreme example of this, abusing mech's lack of map presence and turning Starcraft into World of Hatcheries:
Unlike mech, however, bio forces Zerg to play a low econ game. Zerg can't even take their 3rd until over 7 minutes into the game, where they spawn 9 mutas just to keep terran in their base. After that Zerg techs to hive off 3 hatcheries, and tries to stay alive with defilers while grabbing a 4th gas and ultras (in the most standard game ever). In short, Zerg's economy is much weaker. Their expansions are limited, as is their luxury to produce drones. This is fine vs a medic marine army, which can be combated with a lower econ by using defilers and lurkers to make the most out of your units (until ultras show up).
This is not fine, however, against mech, where Zerg can't play low econ with muta harass and defiler pushes. Vs mech, Zerg just needs a ton of stuff: bases, drones, army, expansions, and hatcheries. That's the beauty of the bio --> mech switch. It forces Zerg to play on a lower economy, and then punish them for it by going mech. Pressure from medic marines doesn't allow Zerg the economy they would usually be able to get vs a pure meching terran. With that, the terran death ball becomes so much harder to fight.
Killer vs Skyhigh offers a good illustration of how this strategy limits Zerg's expansions and economy.
Now, I realize the picture I'm painting is a little more bleak than reality. The bio --> mech switch isn't the end all strategy, and its been beat several times. Zergs have still found ways to push before the transition is complete (Jaedong vs Skyhigh on Fighting Spirit), and even after Terran has switched Zerg have still won by powering hydra / muta / ultra (Jaedong vs SSak on Eye of the Storm, or Jaedong vs Midas on Odd Eye). The strategy is, however, very powerful, and it's something that's been giving Zergs a lot of trouble. It seems as if the only way for Zerg to win is to outplay the Terran, which doesnt seem fair. Even when they do, the strategy still sometimes allows Terran to win.
(will insert Jaedong vs Sea video when it's uploaded to youtube).
What more is there to say about the switch? Anything else I'm missing that makes it powerful? And most importantly, what can Zerg do against this? Unlike Fantasy's last gimmicky strat (the vulture drop rush --> valk thingy), this one seems really solid and hasn't shown many weak spots.
I'm a max rank C terran who used this strat as one of my main TvZ strategies for about a month and a half. That's pretty much it though . I'm not the best player in the world, and I'm not Day9 when it comes to analysis but I did my best. I also haven't played BW for 3 or so weeks now, so I might be missing some things that maybe more skilled players can bring to light.
Also I didn't do any map analysis cause Fighting Spirit and Grand Line are the only maps in the new map pool that I've played myself and am familiar with. That being said, it doesn't seem as if this strategy is as map dependent as mech normally is.
EDIT: Quote from Sea about the strategy after defeating Jaedong with it:
- If you have to evaluate the late mechanic strategy
▲ In my opinion, if the Terran has absolute control over the late mechanic strategy, then the Zerg cannot win. If a Terran has really great command over this strategy, there is no way Zerg can win in an average map.