DIAMONDS

Diamonds (ダイヤ, Daiya) is one of the types of gamesplayed in the Alice in Borderland series, characterized as intelligence games. 

Diamonds games include logic, rationality, numbers, math, and probability. These games often involve solving a riddle or playing a tabletop game based on luck and strategy, such as blackjack or mahjong. The higher-difficulty Diamonds games tend to be zero-sum and/or non-cooperative, resulting in only one winner. Sometimes these games tend to have attributes of Hearts, such as reading the rationality of others and exploring their mental strengths and weaknesses.