Version differences have been part of the Pokemon franchise since its inception. Red and Green started a trend of using exclusives to encourage trading, with monsters like Ekans exclusive to Red version and Sandshrew to Blue version. Pokemon Gold and Silver took this a step further by introducing two box art Legendaries - Ho-Oh and Lugia - whose presence in the main plot would differ slight. While each pair of entries approaches their exclusive content differently, some Black and White offerings could point to design ideas for the upcoming Pokemon Scarlet and Violet.