Starcraft AI blog

Yesterday an epic, today a short sharp shock. The game McRave vs. MadMix is a brazen cheese. Why shouldn’t I build my first pylon next to your nexus? Maybe because it couldn’t possibly succeed?

MadMix placed its first pylon in McRave’s mineral line, at the corner of the nexus. I can suggest an improvement: Place the pylon slightly to the left so it blocks access to the indented mineral patch. That is called a manner pylon because it is ever so polite. A probe sent to mine there will run behind the mineral line, slowing down the opponent’s mining. If you’re going to push a pylon into the opponent’s face, you might as well make it a manner pylon, as in the famous game Bisu-Pokju from 2007.

A manner pylon is commonly worth it, given that you have an early probe in the opponent’s base, especially if (as in Bisu-Pokju) it blocks 2 mineral patches: In between trapped workers that have to escape (which I doubt bots have the knowledge to do), workers devoted to attacking the pylon, and workers sent behind the mineral line, it can slow down the opponent’s mining more than enough to make up for its cost. It occurs to me that a bot with mineral locking could avoid some of the cost provided it has the special case knowledge to avoid locking workers to the blocked mineral patch or patches. I doubt that any bot has that knowledge yet, since I’ve never seen a bot place a manner pylon! I would be interested to see how a manner pylon interacts with LetaBot’s path smoothing. If the smoothing is not smart enough, some SCVs might be unable to mine at all—I am imagining SCVs bumping against the pylon trying to follow the shortest path.

McRave assigned 2 probes to tear down the offending pylon. MadMix calmly continued the cheesemaking process, building a gateway, then replacing the destroyed pylon with 2 fresh pylons, then laying down a second gateway, all while sending fresh probes to make sure one was always on hand. McRave seemed unimpressed and carried on with its 1 gateway build.

McRave ought to have been impressed. McRave’s first zealot was out earlier, and it could have held easily with good play. But McRave didn’t seem to know how to react; as it was attacking proxy buildings and mining gas and starting its cyber core, MadMix was killing probes and pulling ahead. The proxy won. Correct play when you get proxied like this is to delay your tech until you have the situation in hand. Your opponent set itself back to perform the proxy, and you can always stay ahead in units.

Don’t blame McRave for missing knowledge. All the top bots, Iron and Tscmoo included, have knowledge gaps wide enough to drive a government cheese truck through. It was only shortly before the tournament that I added smarts to Steamhammer to react on the fly to this kind of in-base cheese (Steamhammer makes a spawning pool if it has 9 or more drones, and will cancel gas or a second hatchery if that helps it get the pool up faster). And Steamhammer doesn’t understand how to react to other proxies like Juno’s (by Yuanheng Zhu) cannon contain (it still relies on a hand-coded counter for that). Bots need a lot of knowledge and it takes a long time to acquire.