Professor of Economics, Institute of Economic Research, Kyoto University, chief editor of Journal of Mathematical Economics.

“Ambiguity”or “vagueness” can be a strategic variable for a party with informational advantage. There is a large class of strategic environments where ambiguity is an important and useful strategic variable, but modeling strategic ambiguity unambiguously is a challenge. I will argue that “ambiguity” can be understood as concealed Bayesian information, and strategic ambiguity can formally be addressed with a minimal departure from the standard theory of Bayesian games.