One of the most essential facts which you should take into consideration and pay attention to is about dealers' methods of revealing the cards. Before starting to play at Blackjack, you should find out the number of decks of cards which are used. This only depends on the casino you are gambling at, as you are given the opportunity to choose from Single deck Blackjack up to 15 decks. During your play you have the chance to double down if you want to. Well, the question is that when is the most appropriate and beneficial situation to do so. The majority of casinos let you apply doubling down on 9, 10 or 11. It's advisable to double down on these totals when the dealer is showing busting cards. The dealer's busting cards include a 4, 5 or 6.