User blog comment:Rgetar/"Math football"/@comment-162.238.217.96-20171123160135/@comment-32213734-20171127063427

You can't: you're trying to open "close open -1 to -2" move. But this move is already open, since there were not such move as "close close open -1 to -2", and initially all moves are open. So, this move (that is opening a move which is already open) would not change anything. This would contradict the rule: "Repeating states is not allowed" (indeed, this would repeat the current state of the game).

By the way, also in the rules it is said: "player can close an open move or open a closed move", that is a player can't open an open move, or close a closed move. But later I noticed, that this is redundant, since this already follows from the rule of non-repeating states.