Variation (game tree)

Although the term is most commonly used in the context of Chess analysis, it has been applied to other games.

It also is a useful term used when describing computer tree-search algorithms (for example minimax) for playing games such as Go[1] or Chess.

It is often as far ahead as a human or computer can calculate; or however long is necessary to reach a particular position of interest.

The principal variation refers to the particular variation that is the most advantageous to the current player, assuming each other player will respond with the move that best improves their own position.

In the context of tree-searching game artificial intelligence – in which this term is most common – it may also refer to the sequence of moves that is currently believed to be the most advantageous, but is not guaranteed due to the technical limitations of the algorithm.