Starcraft AI blog

Krasi0 and LetaBot congratulated me in comments on Steamhammer’s strong 4-1 start in the SSCAIT tournament. It’s too early—5 games are not enough to say, of course. For myself, I have mixed feelings because Steamhammer sprung one of its surprises, and it backfired resulting in the 1 loss!

I gave Steamhammer 5 counter-builds for 7 specific opponents.

• Killerbot by Marian Devecka - 11 pool into spire
• Iron by Igor Dimitrijevic - 2 hatch hydra
• ZZZKBot by Chris Coxe - 9 pool into expo and finally spire
• PeregrineBot - the same anti-rush 9 pool build
• XIMP by Tomas Vajda - 3 hatch before pool into hydras
• ZerGreenBot - the same 3 hatch build
• Jakub Trancik the cannonbot - a 9 pool zergling build

The counter-builds for Killerbot and Iron score about 50% in my local tests. The build vs Iron scored nearly 100% against a November version of Iron, but Iron improves fast! Killerbot and Iron are far more sophisticated than Steamhammer, and only countering their strategies can make up the difference.

I’m eager to see how the 3 hatch before pool build does, especially since Steamhammer still has a terribly weak macro game. The opening is sound against the forge expand of those 2 protoss bots, but I know some of the mistakes Steamhammer will make. And the anti-cannon build for Jakub Trancik is a shot in the dark that I haven’t really tested. Steamhammer ought to tech to guardians once nearby cannons are eliminated, but time was short.

The anti-rush 9 pool build is slow and cautious and it’s effective against the version of ZZZKBot that I tested. (I haven’t tried PeregrineBot; I just hope it’s close enough.) So when I tuned in to Steamhammer vs. Chris Coxe on the stream and saw mutalisks beating up a barren zerg base, at first I thought “Good, it worked.” But no, Steamhammer was losing! ZZZKBot had switched to an entirely different ZvZ build! ZZZKBot built 5 sunkens to hold off lings and then went mutalisks, which counters builds that counter ZZZKBot’s former 4 pool. Steamhammer’s usual ZvZ 12 pool would crush, but instead my evil plot was thwarted. I expect that Killerbot will also find itself countered, and Zia may or may not be able to adapt.

It’s a double-edged lesson in the risk of fixed builds. By the way, Steamhammer’s 12 pool also counters most of Zia’s strategies, but Zia does have 1 strategy that beats it and soon learns. I expect to lose against Zia this tournament.

With enough time, I could find counter-builds for other troublesome opponents. But the best, like Krasi0 and Bereaver, play more strategically soundly and good openings would not make up much of the skill difference. Or at least that’s what I figured. I thought the effort would go to waste.

Next time! Late last night I fixed the double overlord bug, which sometimes caused Steamhammer to spawn 2 overlords when it needed 1. That messed up its opening timings, which led me to write overcautious opening builds in some cases. Expect more accurate openings in January.