An Analysis of Defense in Stronghold

Stronghold continues to unfold and surprise people in the past few weeks. One aspect of Stronghold that is interesting and dynamic is defense. Defense has made powerhouses lose events that seemed like sure bets, and also created opportunities for new powerhouses to emerge.

Defense in Stronghold can be split into three categories:

  1. Shot Defense
  2. Ball Defense
  3. Objective Defense

The first two are the ones we’ve seen played so far, and the most influential ones. The third is difficult, and may not be something we see often, so I’ll only briefly touch upon it.

Shot defense is the most obvious form of defense. Shot defense in Stronghold has ranged from tremendously effective to not effective at all, and it’s efficacy really depends on what teams you have on the field. Shot defense can be further split into a few different strategies:

  • Hit a team while they’re shooting so they miss. This strategy obviously doesn’t work on outer works shooters in eliminations, as they get the same points for a missed ball as they would a made shot. However teams that shoot from the batter, the base of the batter, and empty space can be effected by this in varying degrees. Sometimes you just want to push your opponents out of their shooting location. Other times you want to push one end of their bot so they turn. Other times you can’t actually do as much to your opponents as you might think with this strategy. It varies quite a bit.
  • Put a wall in front of them and force them to either shoot into it or find a different place to shoot from. This obviously doesn’t work on batter shooters, and mostly doesn’t affect teams that shoot from the base of the batter. It also doesn’t affect teams with high or far back release points that can shoot far over tall walls. But even teams that can normally shoot over 54″ tall walls can be hurt by intelligent use of walls that extend over a team’s frame perimeter.
    • At the 2016 Finger Lakes Regional, the #1 seeded alliance had two robots that could shoot over a 54″ tall wall in 5254 and 2791. The #5 seeded alliance of 20, 639, and 1405 knew this, and developed an extending wall to put in front of our shooters.
      Compare this match to this match to see how much damage this did to the #1 alliance’s scoring abilities.
  • Don’t let a team get to their preferred shooting location. This one affects batter shooters and base of the batter shooters the most. I couldn’t find the footage, but a great example of this is the 2016 Montreal Regional. In finals, 5439 sat in the center batter of their tower for most of the match. 3990 used that location to shoot almost exclusively, and this forced 3990 to shoot from less comfortable locations or shoot low goals for the rest of the match. This brought finals to 3 close matches.

The next kind is ball defense, which is playing defense so that your opponents can’t get as many balls as they would otherwise. Balls can be retrieved from three locations. Your secret passage, your opponent’s secret passage, and the center of the field.

  • Defending the balls in the middle of the field is as simple as getting to them first. Those 6 balls are fairly easy to access, and getting them before your opponent can be important.
  • Balls in your opponent’s secret passage are the closest to the goal you want to shoot from, and having access to them can turn a 4 balls/match robot into a 7-8 balls/match robot. Defending it is simple, however, as your opponents won’t try to enter your secret passage if you’ve got a robot nearby that can touch them while they’re trying to grab a ball. However, this can be difficult without assigning a robot to playing defense on that area specifically.
  • Balls in your secret passage are protected for you, making it the most reliable source of balls, but the area can get easily crowded, especially when sometimes all your balls have to come from that area. Playing defense on the end of your opponent’s secret passage can be effective at slowing down opponents, but it can leave your secret passage undefended.
    • The obvious example of this is Waterloo finals, where 3560 slowed down 1114 and 2056 enough to win the event. Finals-3 is here, and while 3560 did accrue a few fouls doing this, it does seem to have significantly slowed down 1114 and 2056’s ability to get balls.

The last form of defense is defending specific objectives. This can mean keeping your opponents from getting captures, breaches, challenges, and climbs. This is very difficult, however, as the rules are built to protect a team’s ability to score. However there are situations where this kind of defensive effort could arise.

  • Defending the capture is difficult, but can be attempted with a combination of ball starvation strategies and smart shot defense. Teams that shoot intelligently or low goal should be able to get a capture so long as they don’t die on the field or continue to shoot high goals despite misses.
    • One interesting point to be made about defending the capture is how this could come into play in qualifications. In one of our matches at the Finger Lakes Regional, 5254 was shooting shots from the outer works. One of the times, we got hit while shooting, and missed our shot. This gave us 5 penalty points, the equivalent of a missed shot, but we ended up coming up short of the capture by 1 ball. Their defense wasn’t effective in a “win the match” perspective, but it did cause us to lose out on a ranking point we otherwise would have had.
  • Another way to defend the capture is to keep opponents from getting back to the batter. The problem here is that 1) staying in your courtyard and playing defense at this point is illegal, and 2) any time you spend otherwise keeping your opponent from getting a challenge is time you’re also not getting the challenge.
  • Defending against a climb is similar to defending the challenge, with a caveat. If your robot doesn’t have a climb, it could be possible to slow down an opponent enough to keep them from climbing while you still get a challenge.
  • Defending the breach sounds ridiculous, but for example, if you know your opponent can’t do the drawbridge, if you can keep them from getting through one other defense (like perhaps the CDF or the Portcullis that may take time to do), you could theoretically neutralize the breach.

Again, most of these objective defense situations haven’t yet come into play, and they still might not, but a full discussion of defense in Stronghold needs to account for these.

When strategizing, given two otherwise equal alliances, a goal might be to maximize ways for your alliance to get balls while minimizing way for your opponents to get balls. That might be using a dedicated defensive robot in some locations, trying to force your opponents to miss shots, or just running an all-out offensive set, timing your cycles intelligently to neutralize defensive efforts of your opponents, and to occupy space intelligently so your opponent can’t.

This can offer up some interesting questions on whether to run three offensive robots, or to run a dedicated defender. I think if your alliance can occupy space intelligently, a three cycler alliance is capable of some incredible scores, while still shutting down some of your opponent’s options. However, depending on the robots you’re facing, it may be more intelligent to defend some specific vulnerable shooters, or to try to shut down one specific source of balls.

Lastly. there are some interesting ideas about defending low goals and defense in qualifications to consider.

  • When facing low goal heavy alliances, parking a robot in front of one of the low goals can increase cycle times dramatically.
  • Blocking both low goals is theoretically possible, as discussed in this thread, however it’s sketchy at best, and getting an alliance partner to try this and dedicate the whole match to this is an odd use of a third partner.

Qualification defense is interesting, because in most matches you want to make sure to get the capture, so all three robots should be playing offense. However there has been some interesting qualification defense played, especially when alliances are overmatched, and they have to try something crazy to win. The trouble is that oftentimes the team you would send to play defense is the least effective scorer on your alliance, and is therefore often a team that may have less experience with defense, they might accidentally commit penalties, or worse, end up with a dead robot. Additionally, sending a robot to the other side of the field can be risky, because getting a capture in qualifications still requires all three robots to park on the batter, and robots on the other side of the field often have trouble getting back to the batter.

Let me know if I missed anything defensively in Stronghold, or if you have any interesting examples of the defensive styles I listed. I’ll edit this post with any new information or things I may have forgotten.

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