Annotations are represented by extra SGF-properties and thus can be treated in a special way . Variations SGF allows you to store variations of the main path of play, which is useful for analyzing different lines of play. The picture to the right illustrates this concept. Variations are usually assigned letters starting with 'A' where 'A' is the continuation of the current line of play. That's why some applications refer to the next move as 'A'.
Applications show variations as either siblings or children.
That is, by selecting a variation, you step forward in the tree. The differences between this two styles may cause confusion when the variations are accompanied by comments. See variation 'B' instead. Most people prefer the sibling style as it seems more natural. They even imitate the sibling style in children-style applications.