Turtle < Expand < Rush
Generally speaking, there are three strategies you can adopt when playing competitive, online, real-time strategy games. These are turtling, expanding, or rushing.
Turtling is when a player focuses predominantly on defense. They do this by building defensive units and structures as opposed to expanding their economy or attacking. Once they feel secure, they move out from their base with a huge army and (hopefully!) steamroll their way to victory. This is a strategy that is common amongst very new players as it enables them to feel in control.
Turtling is countered by expanding. The idea is to grow your economy so fast that you overtake and then overwhelm a turtle. You do this by channeling your resources into acquiring even more resources. Then, when you have built up a huge economy, you transition into building lots of offensive units. Expanders often secure territory across large portions of the map to gain access to as many resources as possible. This is effective against a turtle because a turtle does not contest the map's resources as they are too focused on defense. Expanders typically have very few military units in the early and mid-game but by the late game (which they get to quickly) they will be unstoppable.
Expanding is weak to rushes because a rusher invests in early offensive power. This means they sacrifice their future economy to get an attacking advantage now. Against an expander, this offensive power is met with little resistance, as the expander has spread themself thinly across the map. The result is that the expander is crippled by the rusher, as they have no army to defend themselves. Ultimately this means that the resources they have invested in the future are wasted and they will be overwhelmed by the rusher's forces.
Rushers are ineffective against turtles. This is because the turtle has invested significantly to defend against early attacks. They do this by getting units and structures that have strong defensive characteristics (like armor or zone control) as opposed to good aggressive characteristics (like speed). Most RTS’s place a premium on aggressive units, so it also means that defensive units will be cheaper in relation to their combat value. Due to this not only will they win early defensive fights but they will also spend fewer resources doing so. The outcome of this will be that the turtle has a stronger economy, units left over from the initial fight, and a better-defended base than the rusher. A smart turtle will then be able to capitalize on this advantage to win the game.
As you get better as a player the line between these strategies becomes more blurred and fluid. Often you will switch out of one mode and into another as the match develops.
For example, if a rush fails to destroy a turtle early on their only option might be to transition into an expansion strategy. They know their rush didn’t work, so to continue to do that is futile and they can’t adopt a turtle strategy because their opponent will always be ahead. This would make them very vulnerable for a period of time, but if they can survive they might be able to eventually overcome the turtle.
So how do you know which strategy to adopt? Well, it all comes down to vision. In my next article, we will go through why vision is important, when it is needed and how to get better at it. Until then!