The "Illustrious 18" is a set of 18 strategic deviations from basic blackjack strategy, designed to enhance a player's edge when using card counting, particularly with the Hi-Lo system. These deviations are triggered by the true count (a refined version of the running count) and help adjust decisions like when to stand, hit, double down, or split, based on the deck composition. For example, you might double down on a soft 18 or stand on a soft 17 when the count is high. To use the Illustrious 18 effectively, players must be able to accurately track the count and know when to apply these deviations. This strategy can increase a player's expected win rate by 1-2%, but it requires a solid understanding of card counting and consistent practice to implement correctly.