Go Thermography: the 4/21/98 Jiang--Rui Endgame

Go thermography is more complex than thermography for classical combinatorial games because of loopy games called kos. In most situations, go rules forbid the loopiness of a ko by banning the play that repeats a position. Because of the ko ban one player may be able to force her opponent to play elsewhere while she makes more than one play in the ko, and that fact gives new slopes to the lines of ko thermographs. Each line of a thermograph is associated with at least one line of orthodox play [Berlekamp 2000, 2001]. Multiple kos require a new definition of thermograph, one based on orthodox play in an enriched environment, rather than on taxes or on composing thermographs from the thermographs of the followers [Spight 1998]. Orthodox play is optimal in such an environment.