Blackjack is a bit unique among casino games as there's actually a good bit of strategy as far as how to play the game. While there are various betting strategies for nearly every casino game, blackjack strategy is different, as there are proven, optimal ways of playing various combinations of cards, based on what the dealer has.

Because of the nature of how blackjack is played (with the players cards displayed and one of the dealer's cards dealt face up) determining whether a player should take another card or stand pat can be calculated mathematically, as far as what's best for the player according to the odds. These calculations are called "blackjack basic strategy", so if a player plays "perfect basic strategy", it means they're making all of the best decisions, based on the odds, instead of hitting when they feel lucky, etc.

For charts that summarize basic blackjack strategy for every hand (and for different games), WizardofOdds is a great resource. Players can simply print out the strategy charts for the game they're playing and use them to guide them when making decisions. This is not only legal to do online, but in brick and mortar casinos as well.

Remember, playing perfect basic strategy reduced the house advantage greatly, but the odds are still slightly in favor of the casino, which is why they allow you to use strategy cards at the table, if you want to. It may seem like it's "cheating" but it's actually far from it, as the house still has an edge.