the representation of all possible paths of research a player can take. Analysis of the tech tree leads to specific paths that a player can take to optimally advance specific strategic or tactical goals. These optimized paths are build orders. For example, a player who plans to launch an attack by air may only build the structures necessary to construct air units and may research only the technologies which enhance the capabilities of air units. The order in which to build those structures and research those technologies is known as a build order. The same player could instead choose a slightly different build order that goes for air units but also creates a small ground-defense army – this would be a more defensive, less risky choice at the expense of having maximum airspace power. As you can see in the list above build orders are usually used to determine how a player will start the game, which is why they are often miscalled "openings". There are many reasons for this: a flawed game start could mean that you lose the game early on, so it is important to have resilient openings; how you start a match most often than not narrows the middle and late-game options so the very first few choices alone dictate your future options; middle and late game choices require you to study the current situation so not only are they harder to plan ahead but then one also has more time to think, while on the very beginning it is more advantageous to have a fixed plan and execute it as fast and precisely as possible. Build orders can also plan ahead for late-game scenarios but that is less common. Build orders often involve significant timing issues. This applies to both turn-based and real-time strategy games. In turn-based games, specific buildings and technologies will take a specific number of turns to complete. A build order may involve waiting until specific turns to begin building the next building or researching the next technology. In real-time strategy games, timing may be even more crucial. To execute an optimal rush, a player will not only have to know exactly what to build or research but also when to do so. If the build order is altered in any way, the units or structures may not be produced as quickly. The delay may mean the difference between a game win