A Zero-Sum Game is one in which no value or wealth is created. One party’s win is the other party’s loss. In such a game, the best strategy often is to minimise losses. Information asymmetry may play a big role in winning such games.
Chess and tic-tac-toe can be seen as zero-sum games with perfect information symmetry. In finance, futures and options are zero-sum games. For every contract’s gain, there is a counter-party who loses.