6. Sentry/Forcefield Use

Hey Guys, I thought I'd write a post about The Protoss Sentry. The Sentry is a support unit created out of the Gateway or Warpgate. It requires a Cybernetics Core to be built and requires 50 minerals and 100 Gas. I often build Sentries early so they have time to charge by the time i engage.

The bread and butter skill of the Sentry and arguably Protoss  race as a whole is Forcefield. The spell basically creates a dome of energy that enemy units cannot pass through over ground. (However, Massive units such as Colossus, Ultralisks and Thors destroy forcefields upon coming into contact with them.) First I'll go into some ways the spell can be used.

Forcefielding the Ramp-  Using a forcefield on a ramp is a great way to cut an army in half. If an enemy army is in the process of moving up or down a ramp, use forcefield directly in the middle to effectively cut his forces in two. This technique is especially effective against players who try to push up your ramp early game. It is also good for containing a player in his base. Many times I've had a single corsair harass a zergs overseers in his main to draw his army back there.. Moved my army to his natural.. Forcefield his ramp and leave his forces stuck in his Main while I killed his natural and all of the drones there.

Versus Zerglings- Zerglings thrive on being able to surround the enemy units. Use your forcefields to create less surface area for the zerglings to attack by placing forcefields around your army so that there is no space for them to attack. This makes dealing with zergling heavy armys much, much easier.

Versus units with shorter range- You can make a wall that allows your longer range units to attack them without being attacked back. For example Stalker vs. Marine you create a make shift wall at a choke point move your Stalkers out of the Marines range and go back to attack them. Forcefields work especially well with Colossi in play. Placing barriers between the enemy force and the colossi allows the colossi to further take advantage of their extremely long range because the enemy force either has to funnel throught he small cracks in your wall or cannot get through entirely to do damage.

Creating a Tighter Choke Point- This is very effective when the enemy is a lot more 'melee heavy' in his army composition. What you want to do is create a 'funnel' so that not all of his melee units can be doing dps but all of your range units are dealing damage. Most of the time enemy players will retreat in this situation in which case you can make another wall to slow their escape and further maximize the amount of damage you're inflicting.

Disrupting Your Opponents Concave- I'm sure you've noticed that most fights between ranged units result in a sort of concave or semi-circle shape in the armies, In this case forcefields can be used to disrupt this formation and force your opponents forces to reposition themselves. Just place the forcefields right in the middle of his lines. A little trick I've been experimenting with is when the opponent retreats from the forcefielded position, place on more forcefield on top of the other 2 forming upside down V's, or a checkerboard.

  X  X        (place these when he may retreat)
X  X  X     (place these initially to break up the Concave)

There's really unlimited ways to use forcefields, but these are just a few that I try and use regularly. Also note that you should try to get as much of your army as possible under your GS (Guardian Shield) so you have more forcefields to use.

Some things to note about Sentries
Sentries have 40hp and 40 shields and die fairly quickly. Sentries have a range of 5, meaning they can be placed in front of Stalkers and behind Zealots for a 'Triple Layer' of damage. They do almost as much DPS to light units as a Stalker, but have trouble killing armored units. A Sentry has 200 energy meaning you can get off 4 forcefields off of one fully charged Sentry (Or 2 and 1 GS). Typically you want to have 4-6 sentrys in your army, Although some top level Protoss such as HuK preffer having more. Good Luck, Have Fun guys :)

8/4/2010