  We develop a theory of combinatorial games that is appropriate for describing
positions in Hex and other monotone set coloring games. We consider two natural
conditions on such games: a game is monotone if all moves available to both
players are good, and passable if in each position, at least one player has at
least one good move available. The latter condition is equivalent to saying
that if passing were permitted, no player would benefit from passing. Clearly
every monotone game is passable, and we prove that the converse holds up to
equivalence of games. We give some examples of how this theory can be applied
to the analysis of Hex positions.
