Starcraft AI blog

Steamhammer-Joon is a funny game played today on SCHNAIL. (The player’s screen name is ZI7HMI and the game time was 21-06-30 08:48:50.) Steamhammer had played this opponent once before and correctly predicted cheese, so it started with 9 pool and a sunken in its main. Joon, being a crafty human rather than a bot, crossed this plan up by bunkering the natural below the ramp. At the time of this picture, the first terran barracks had lifted because it had started to burn, and the initial zerglings that escaped before the bunker were attacking SCVs.

Zerg was mining with more workers than terran, but was contained to its base—and terran sent most of the pulled SCVs back home, putting the human ahead in economy. Steamhammer kept sacrificing drones to the bunkers as it tried to expand (it’s on my list to fix soon with safe pathfinding), and losing overlords for lack of understanding of enemy visibility. But it also got lurkers, and terran was only just adding comsats. After a sharp struggle whose outcome looked uncertain at first, zerg broke its own natural—where terran had built a command center—and forced buildings to lift.

Now terran was far ahead in economy though with hands too slow to spend it, while zerg was ahead in army. Notice that terran is adding a starport while zerg is getting a spire. The zerg force, finding no buildings on the ground and unable to attack air, hurried across the map to the terran side. Immediately, Joon landed the buildings again, so that the drone which came down to expand could not take the natural but had to continue to another base to expand. Having crossed the map, lurkers forced the terran natural into the air and continued on to pillage the main, while terran quickly trained marines in the zerg natural and easily held it, restoring the containment—but with zerg already owning a base outside it.

In the picture you can see 2 vultures and a wraith, which proved of little value. Steamhammer scourged the wraith and a followup wraith (you can see the scourge in the production tab). At the opposite corner of the map, terran marines were supreme and Steamhammer chose a mutalisk switch, which was also of little value. The strategic situation completely reversed in a short time, with zerg ahead in economy and terran stronger in army. Steamhammer had taken the top center base, but was not mining there.

Steamhammer killed all SCVs in the terran main, left 1 lurker there to finish cleaning up, and returned the other 3 to visit the terran complex at the zerg natural. At the same time, the strong terran infantry easily broke the sunken in the zerg main, which had been waiting there since the early opening, and set about their own cleanup. Base race!

A crazy game, and a close one. Both players had opportunities to turn events in their favor at multiple points. I won’t spoil the end, though it’s predictable if you know how terran-zerg base races go. You can watch it to see.