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developing an anti-vulture opening for Steamhammer

I decided I was tired of seeing Steamhammer lose helplessly to Iron’s vulture runby and Tscmoo’s factory openings. Terran can start with vultures and force zerg to defend: Zerglings quickly become useless, drones are at risk, and terran can run by defenses into the main as Iron does. Steamhammer’s strategy boss understands that a sunken is needed at the front, and has a vague idea that hydralisks may be useful if the book line happens to end, but in the end it doesn’t defend adequately. Then terran can follow up with more factory units or with wraiths, and zerg has to be ready for a range of possibilities. Against Steamhammer, Tscmoo likes to follow up with goliaths, which is effective against Steamhammer’s mutalisk openings. Too many crushing losses.

Zerg has a standard way to defend: Place a sunken at the front as a vulture obstacle and keep a modest number of unupgraded hydralisks in a defensive position. The hydras are general purpose and can fight off vulture runbys, wraith harassment, small drops—all the natural followups. Zerg then continues to mutalisks as usual. The mutas are delayed, but terran is playing a slow strategy so it’s OK.

Today I set about developing an “AntiFactory” opening that implements the standard defense. I decided on development tests against Iron to see whether the runby defense works. In the very first test, when the opening timings were still all screwy, Steamhammer put up a persistent defense and didn’t lose until well into the middlegame. An improvement already, good. I made a few fixes and tried again. Steamhammer held the early aggression cleanly and fought a long level game until Iron finally mined out and collapsed.

I did not expect that! Steamhammer lost drones by the barrel and miscontrolled scourge and chased 1 SCV with 3 ultralisks, all its usual mistakes, but Iron struggled too and could neither stop zerg from expanding nor keep a fourth base up. I guess Iron depends heavily on the success of the early vulture runby.

Well, one win does not make a champion. We’ll see how it goes as I polish the opening. It’s just that the test game was so long that by the time I finished watching it, I had forgotten what needed fixing in the opening....

When the opening is ready, will the opponent model be able to select it when it should? I think the answer is no. I think I will have to extend the plan recognizer to recognize early vulture plans. Then Steamhammer should be able to counter the vultures in the second game, and ideally cope with the followup. It would be nice if Steamhammer could get back into the learning war against Tscmoo terran, and come out on top this time.

AntiFactory branches fairly late from related openings. When the opening tree is available, Steamhammer should be able to recognize the vulture plan during the game and choose the right build on the fly, more like a human player. It might need some scouting improvements first, though.

Next: The new bots GuiBot and WillyT.

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Comments

Antiga / Iruian on :

If not doing a hydra first opening and one that uses lings the standard way to do it is place the sunken in such a way that it covers the ramp / entrance and put 6-8 lings on the ramp to block the vulture. A properly placed sunken should also be able to hit the vulture at the ramp block for it to work properly. It should allow opening 2 and 3 H muta (the standard counters to factory openers). Really in human play opening mech is almost a solved problem, and can only be done as a surprise move not everygame. As the counters are well understood.

Jay Scott on :

CherryPi knows how to position the sunken and block the vulture runby with zerglings. I think it’s the only bot with the skill. Steamhammer won’t start to get skills like that until I work on tactical analysis. In the meantime, it’s interesting that strategy skills can substitute for so many tactical skills.

Marian on :

Actually mech openings are having a comeback.
They provide more flexibility than neo standard 5 rax openning.
In recent interview Flash had great insights on that - also published on this site.

Antiga / Iruian on :

I tend to think 1-1-1 isn't traditional mech, it's more of a mech M+M hybrid. That build is fairly new, and there isn't really a direct counter for it quite yet. Likely will be someday soon.

MicroDK on :

I think it is a matter of CherryPi prefer to defend at chokes and is good at positioning its sunkens...

Jay Scott on :

CherryPi doesn’t block with its zerglings, but it doesn’t need to because it doesn’t have human limitations on attention or speed. My interpretation of its behavior is that it actively moves the lings to intercept the vultures, and makes sure it does so behind the sunken and still in its range. Whether you call it the usual defensive behavior or not, it’s a behavior that is good for blocking.

Nick on :

Is there any research to block so called "run throughs"?

Jay Scott on :

Not sure what you mean. Steamhammer does like to sometimes run its army through the enemy forces and lose everything. Is that it?

krasi0 on :

I think he meant "runbys"

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