Fresh Position

Patrick Traill suggests the term “fresh position” for a position in a game such that no position after it can be the same as any leading up to it, given optimal (or moderately rational) play. Examples are filling a dame between two live groups or is creating a definite eye, as may happen as a ko threat and answer. This can be useful when discussing superko, as in the article “Bent four in the corner is dead”, in the section on doubly infinite supplies of threats.

In practice a fresh position is created by most moves, as most moves occupy a previously unoccupied point, are destined not to be captured and indeed cannot be captured without a sequence of other moves altering other parts of the position. In theory, however, (almost) any position could be recreated by absurd cooperation between both players, using a suitable combination of passing and filling liberties until one player captures the entire board, that player then filling their own liberties until their opponent can capture them with a single stone, recreating an almost empty board and then recreating the position in question; by judicious passing one can probably also avoid recreating any earlier positions until the desired one is reached.