On this page 4-Deck to 8-Deck Blackjack Strategy Introduction Rummy (Blackjack variant popular in Costa Rica).21: Details on the Wizard\’s Simple Strategy.20: Blackjack doubling strategy when doubling after splitting aces is allowed.19: Blackjack splitting strategy when a back-player is betting.18: Basic strategy exceptions for three to six cards.16: Basic strategy when dealer exposes both cards.15: House edge using total-dependent vs.13: Probabilities in the first four cards.