Life isn’t so simple that there’s an optimal strategy that will work in all situations. What works best depends on many variables factors determined by the environment, other people, and pure chance. In a competitive environment, this becomes very similar to a game of rock-paper-scissors in at least two respects. Firstly, the effectiveness of your choice depends on that of your opponent. E.g., a rock isn’t good or bad in itself. It is good against an opponent’s scissors and bad against his paper. What makes the game (and life) interesting is that you often have to make your decision before you get to know of your opponent’s choice. From my modest experience with real-time strategy (RTS) games, I find that the broad strategies in a real-time strategy game fit into a similar pattern, which I hope will be clearer as we explore the rock-paper-scissors of real-time strategy games.
In an RTS, there are three broad strategies that players may choose – offensive, defensive, or economic. Offensive usually involves attacking the opponent early on. This means that you compromise your economy, hoping to hurt the enemy even more and stunting their growth, if not finishing them off completely. The best counter to an offensive opponent is to play defensively. In this case, you don’t sacrifice too much on your growth, but at the same time build some fortifications around your city and maintain a small army that will help defend against an early attack. A rush or raid against a defensive opponent is likely to fail and result in heavy losses for the attacker who will be short on resources and lagging in technology. The best strategy against an opponent who plays defensively would be to completely ignore his existence in the early stages of the game and focus fully on expanding your own empire and economy. This way, you will be able to get ahead of your opponent because the resources he spent on fortifications or a standing army can be diverted to fuel growth and expansion. Once you’re significantly ahead and well established, you can amass a huge army and crush your opponent with overwhelming force. Remember, however, that the booming economic player will be a sitting duck against an offensive player.
I think of the economic game as “paper“, perhaps because it is the “plain” style followed by most new players who think only of growing in the initial stages and begin war only in the final ages, when their economy is more or less stable. Whether they follow this strategy because it works well against easy AIs, or if easy AIs are designed that way to match a beginner’s natural style, is hard to tell. (Personally I believe it’s the latter)
The offensive game is the “scissors” that can shred this paper, and is used by intermediate gamers who know that a boom game will often end in prolonged conflict and uncertain results. They will seek to achieve a quick victory by rushing their enemies in the early ages. This strategy works quite well against most AIs, and is also employed by some of the harder variants.
One who has faced a few rushes is sure to build “rock” solid defences around his town that can blunt or break the blade of an early attacker. However, a plain (paper style) economic game will likely be able to cover the defensive player from all sides and beat them in the end-game. So, if he does not face any attacks in the early game, he would ideally want to finish it in the middle ages before the other player is able to complete his grand scheme.
So which style should one choose to have victory assured? If you got what I’ve been trying to say so far, there is no optimal strategy like that. Good players will be able to play any of these styles (depending, often, on the map or the bonuses of the civilization they’re playing). What style they actually start with will often depend on gut feeling and their psychological reading of the opponent. They will also be able to change their styles mid-game, adapting to the opponent’s way of playing.
Against an opponent you know nothing about and who knows nothing about your style, the best bet would be to play the style that you are the best at. That way, you can get a win if he chooses the style that is weak against yours, and possibly win or at least give a good fight if he also chooses the same style (depending on who executes better). Against an opponent who’s as good as you, this gets closest to the probability of victory in a game of rock-paper-scissors.
If you know that the other player has a single specialization which he uses every time, and he cannot use anything else, then it makes sense to go with the style that can counter it. If you know that the opponent can use two styles but not the third, then it would be wise to go with what game theory would call the dominant strategy. For example, if you know that you are going to get either a rock or a scissors, then choosing a paper will mean either win or loss. Choosing scissors will mean a loss or a stalemate, while choosing rock can ensure a victory or a stalemate. Clearly, rock would be the best choice here assuming you can play all three styles equally well!
If you know that the opponent can play all three styles, and he doesn’t know your style, it would be best to play your own specialization (as in the case of an unknown opponent). If you also can play all three styles equally well, then choosing your style in a random way will at least limit your opponent’s ability to predict and counter it. If you can play two of the styles and the opponent knows it, then you can choose the dominant strategy if you can trust your opponent to also depend on game theory. However, if your opponent knows your faith in game theory and chooses the third option, then you’re done! This again shows how similar this situation is to a simple game of rock-paper-scissors.