But (and please verify that carefully) it will not matter: The only thing required from that field is that there is a second field that, together with the center, forms a row (or column or diagonal) all fields satisfy that. The only way I can influence the game is by chosing which ○ I place last this determines where Denis goes now. Doing this eight times inevitably puts us in a position like this: No matter where I place it, Denis will send me back ot the middle, until one field of the center game is free. Now I have to put my ○ in the center field of the center game. Like most suggestions for a winning strategy for the first player, Denis (X) starts with the middle: │ │ Update: Not surprising, but with these variants of the rule, the winning strategy was already known.Īssume Denis (⨯) plays against me (○). We discussed this a bit in our office, and my coworker Denis Lohner came up with what seems to be a winning strategy.

See the linked article for a full explanation.Īs far as I know, the question of who wins this game was open at least nothing definite was known on Hacker News or on the Board Games StackExchange site. If you chose a field in the small game, this position determines the small field that the other play may play next. To mark a field of the large game as your, you have to win the small game therein. The blog Math with Bad Drawings recently featured an article about Ultimate Tic Tac Toe, a variant of Tic Tac Toe where each of the nine fields is a separate game of Tic Tac Toe.

Ultimate tic tac toe boards