Sungguk Cha

Sungguk Cha is currently one of the weakest bots on the SSCAIT ladder in terms of results, but its play is far more complex than what one might expect. It loses around 4/5 of its games, but its strategy strongly resembles that of bots like Iron which win around 4/5 of their games.

I thought that a bot that on paper looks very strong but underperforms would be a good place to start on my reviews of bots, as it gives me a lot to talk about.

Strategy:
The bot’s strongest asset. It begins with bio, then transitions into mech, with a huge number of vultures backed up with tanks, then builds wraiths. I’ve never seen it, but I wouldn’t be surprised if it’s also able to build battlecruisers and/or science vessels if it can get far enough into its build order. The build strongly reminds me of Iron, Tscmoo and Tyr’s builds from around Spring 2016, when they were the strongest Terrans on the SSCAIT ladder.

Macro:
Surprisingly for such a weak bot, Sungguk Cha is good at taking expansions at sensible times, and also seems reasonably good at keeping map control to defend them. Even some of the strongest bots (Krasi0, for example) have had problems with taking third bases (admittedly against far stronger opponents than those that Sungguk Cha is able to beat).

However, something that I’ve noticed is common in bots that underperform, includng Cha, is excessive gas harvesting. I’ve seen this bot float over 10,000 gas, while still struggling to mine enough minerals. From what I saw of the bot’s base, its saturation of its mineral lines seems sensible (it uses a few too many SCVs on minerals, if anything), but there seem to be problems with pathing and/or distribution of SCVs between mineral patches.

The strategy is certainly very good, but it does seem a little too vulture-heavy, and a shift to include more tanks or get Starport tech out sooner would help to balance the economy and make the army stronger. Just moving SCVs from gas to new mineral lines when there’s a big surplus of gas would help somewhat.

Micro:
Probably the main reason this bot underperforms.

A common and serious error of several weak bots that Sungguk Cha makes is not having its army together when it engages. It sieges its tanks across the map rather than together in a group, and when it attacks with vultures it only moves a handful in at a time.

The wide and sparse tank positioning works well as a stalling tactic, allows greater map control which helps prevent harassment, and means the tanks aren’t affected by splash damage. This may have benefits in some situations, but it means that the army invariably loses against other late game armies in a head-on fight.

The massed vultures are used to make a large minefield, which isn’t as neat as that of other bots like ICElab, but is still very effective against bots without detection, and couples with the tanks as a stalling tactic to allow wraiths to get out safely. There does, however seem to be a bug where vultures freeze when enemy units enter their line of sight. I believe this may be the result of vultures being ordered to lay mines and attack the approaching enemies at the same time, or possibly some other clash of contradictory instructions. Whatever the cause, it’s a serious disadvantage when some units don’t move or attack, and simply fixing this could make the bot far more powerful.

I initially believed that Sungguk Cha’s bot did not use kiting micro, but it actually does in some situations. I have seen it kite its vultures against zerglings, but not zealots. This may be related to the previously mentioned “freezing” bug, or it may simply be that kiting has been programmed as a response to zerglings but not zealots.

If you’ve got any of your own ideas or comments about this bot, feel free to post them below. If you’ve got any questions about this bot, I’ll try my best to answer them (though it’s likely I’ll have no idea what the answer is). If Sungguk Cha comes around here, hi, I hope that my comments are helpful, or at least interesting.

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