Turn Structure

Starcraft is not a turn-based game. Players are free to take any action at any time.

However, players executing a strategy want to take certain actions as soon as possible after a certain condition is met, but not before. For example, a player may want to queue an SCV as soon as the SCV queue is empty, but not before.

The player who wants to take actions this way has to constantly collect up-to-date information from a variety of sources, such as the minimap, the information panel, the screen, the clock, the resource counters and others.

In general, not all the information is readily available, and the player has to take some actions, typically selection actions and camera actions, in order to gather the information.

This process may take a considerable amount of time, depending on the number of conditions that the player wants to check, depending on the complexity of collecting partial information and computing whether the condition is met.

A player can design, practice and master a technique to collect this information in a well-thought and structured way. Such a technique may define a sequence of actions (and optional reactions) that the player wants to execute in a continuous loop. An execution of this sequence of action-reaction is called a turn, and a model of a turn is called turn structure.

Common components of a turn structure include:

to check whether there is an avaliable slot in the SCV/probe queue, and if so, queue a SCV/probe

to check how many workers are collecting gas

to check whether there is an available slot in the barracks, factories, warp gates

to check whether it is possible to calldown: mule, or to cast spawn larva.

to check whether there are too many workers mining minerals

to check whether there are idle workers

to check whether there are brand new units that are waiting in the rally area