A thrilling layer of strategy is added to each round of Gin Rummy as players try to "knock" when they think their opponent has more unmatched cards than they do. Rummy variations that are widely used. Irummy gopdndian Rummy is another popular variation that combines aspects of Gin Rummy and traditional Rummy. However, it frequently requires players to form at least two sequences, one of which must be a pure sequence (i.e., without wild cards). This version's captivating gameplay and social features have made it extremely popular in India and have gained popularity worldwide. learning novel strategies & rules.